/ 

I 


DETAILS  OF  PRACTICAL  MINING 


BOOKS  COMPILED  BY 

EDITORIAL  STAFF 
ENGINEERING  AND  MINING  JOURNAL 


HANDBOOK  OP  MINING  DETAILS 
372  pages,  6X9,  250  illustrations $4.00 

HANDBOOK  OF  MILLING  DETAILS 
422  pages,  6X9,  241  illustrations $4.00 

DETAILS  OF  PRACTICAL  MINING 
544  pages,  6X9,  440  illustrations $5.00 


DETAILS 


OF 


PRACTICAL  MINING 


COMPILED  FROM  THE  , 

ENGINEERING  AND  MINING  JOURNAL 


BY 

THE  EDITORIAL  STAFF 


FIRST  EDITION 


McGRAW-HILL  BOOK  COMPANY,  ING. 
239  WEST  39TH  STREET,  NEW  YORK 

6  BOUVERIE  STREET,  LONDON,  E.  C. 
1916 


COPYRIGHT,  1916,  BY  THE 
MCGRAW-HILL  BOOK  COMPANY,  INC. 


T  11 K    MAl'LE     fHESS     YORK.    1*  A. 


PREFACE 

In  1912  We  published  the  first  "Handbook  of  Mining  Details,"  the 
purpose  and  scope  of  which  were  briefly  outlined  in  the  preface  as  follows: 

This  book  is  a  collection  of  articles  that  have  appeared  in  the  Engineering  and 
Mining  Journal  during  the  last  two  or  three  years  under  the  general  head  of  "  Details 
of  Practical  Mining,"  a  department  of  the  Journal  that  has  been  appreciated  highly 
by  its  readers,  many  of  whom  have  expressed  the  wish  that  a  collection  in  book  form 
be  made,  which  has  now  been  done. 

In  the  editing  of  this  volume,  the  work  has  been  chiefly  in  the  selection  of  the  mate- 
rial and  its  arrangement  in  chapters.  Now  and  then  it  has  been  possible  to  excise 
some  paragraphs  as  being  unessential  and  occasionally  the  phraseology  of  some  articles 
has  been  altered  a  little,  the  requirements  of  preparation  for  the  original  weekly 
publication  not  always  having  permitted  leisurely  consideration,  but  in  the  main  the 
articles  now  presented  in  this  book  are  as  they  were  given  in  the  pages  of  the  Engineer- 
ing and  Mining  Journal.  However,  it  has  been  necessary  in  a  few  cases  to  reduce 
the  size  of  the  engravings. 

In  making  this  collection  the  limitation  of  space  necessitated  the  rejection  of  all 
material  that  did  not  pertain  to  the  subjects  selected  for  the  chapters  of  the  book,  and 
even  so  it  was  necessary  to  dismiss  some  of  the  longer  articles  pertaining  to  them,  which 
approached  the  character  of  essays  rather  than  being  the  description  and  discussion 
of  details.  Of  course  a  wealth  of  contributions  pertaining  to  the  arts  of  ore  dressing 
and  metallurgy  had  to  be  rejected  summarily.  The  compilation  covers  the  publica- 
tions in  the  Engineering  and  Mining  Journal  from  Aug.  7,  1909,  to  July  1,  1912.  If 
all  of  the  material  that  appeared  in  this  department  of  the  Journal  during  that  period 
of  three  years  had  been  used  it  would  have  been  necessary  to  make  a  book  of  several 
times  the  size  of  this. 

No  claim  is  made  that  this  book  is  a  treatise,  exhausting  its  subject,  or  any  part  of 
it.  It  is  simply  a  handbook  that  is  a  more  or  less  random  collection  of  useful  informa- 
tion, being  just  what  passes  through  the  pages  of  the  Engineering  and  Mining  Journal 
in  the  course  of  a  few  years.  No  special  attempt  to  round  out  any  subject  has  been 
made,  yet  it  will  be  found  that  some  subjects  are  fully  treated. 

With  regard  to  the  authority  of  what  is  to  be  found  in  these  pages :  The  matter  in 
the  main  is  merely  descriptive  of  what  is  done.  Nevertheless,  there  is  frequently  the 
injection  of  opinion  and  advice.  A  great  technical  journal  is  directed  by  its  editor 
and  is  shaped  by  its  editorial  staff,  but  it  is  essentially  the  product  of  its  contributors. 
It  is  a  co-operative  institution  and  its  pages  are  a  symposium  of  the  experiences  and 
views  of  many  professional  men.  During  the  18  months  ending  with  June  30,  1912, 
there  were  460  contributors  to  the  Engineering  and  Mining  Journal,  exclusive  of  the 
members  of  the  editorial  staff,  and  its  regular  coadjutors,  and  its  news  correspondents. 
Many  of  these  contributors  furnished  articles  that  are  now  collected  in  this  book. 
Their  articles  generally  are  signed.  The  unsigned  articles  are  chiefly  the  work  of 
members  of  the  editorial  staff  of  the  Journal  who  have  been  sent  into  the  field  to 
study  mining  practice. 

The  heterogeneous  authorship  of  this  book  naturally  gives  rise  to  some  inconsist- 
encies, some  differences  of  opinion  and  some  conflicts  in  advice.  It  has  seemed  to  me 

33fl69 


vi  PREFACE 

best  to  let  these  stand  just  as  in  the  original,  since  they  are  often  merely  the  reflection 
of  different  conditions  prevailing  in  different  parts  of  the  country,  and  if  carefully 
read,  absence  of  unity  in  this  respect  will  not  be  misleading. 

The  publication  of  this  volume  was  favorably  received  and  there  was 
a  considerable  expression  of  the  opinion  that  a  similar  book  should  be 
issued  later.  The  idea  was  conceived,  therefore,  of  publishing  such  a 
volume  every  two  or  three  years.  The  present  volume  is  issued  in  con- 
formity with  that  idea.  With  respect  to  its  nature  and  scope,  scarcely 
anything  remains  to  be  added  to  what  was  said  in  the  preface  to  the  first 
volume.  The  main  plan  remains  the  same  and  the  nature  of  the  material 
incorporated  is  similar,  but  the  classification  in  chapters  and  subdivisions 
thereof  is  more  systematic.  This  book  includes  matter  that  appeared  in\ 
the  Engineering  and  Mining  Journal  between  July  1,  1912,  and  July  1,1 
1915. 

The  preparation  of  this  book,  like  its  forerunner,  is  stated  on  the  title 
page  to  have  been  by  the  editorial  staff  of  the  Engineering  and  Mining 
Journal,  and  in  fact  every  member  of  the  staff  worked  upon  the  original 
presentation  of  the  material  in  the  pages  of  the  Journal.  The  selection 
and  arrangement  of  the  material  of  this  book  and  the  revision — which 
has  been  carefully  and  intelligently  done — was  the  work  of  (Lej^O.  Kellogg, 
until  recently  a  member  of  the  editorial  staff  of  the  Engineering  and 
Mining  Journal.  Mr.  Kellogg  is  also  the  author  of  many  of  the  articles 
appearing  in  these  pages,  and  to  him  belongs  chiefly  the  credit  for  the 
preparation  of  this  volume. 

W.  R.  INGALLS. 
October  1,  1915. 


CONTENTS 

PAGE 
PREFACE     . v 

CHAPTER  I 

SURFACE  PLANT  AND  OPERATIONS 1 

Sectional  Portable  Camp  Buildings  (by  George  S.  Rollin) — Inexpensive 
Miners'  Dwellings  (by  P.  E.  Barbour) — Ventilating  Bunkhouses  (by 
George  S.  Rollin) — Trench  and  Pipe  Feed-water  Heater — Timber  Founda- 
tions for  Engines  (by  A.  Livingstone  Oke) — Foundations  for  Prospecting 
Machinery  (by  Horace  F.  Lunt) — Automatic  Belt  Tightener  (by  J.  R. 
McFarland) — Hillside  Pipe-line  Anchor  (by  W.  R.  Hodge) — Cheap  Expan- 
sion Joint  (by  Fred  D.  Smith) — Variable-Stroke  Air  Hammer  (by  J.  R. 
McFarland) — Stand  for  the  Blacksmith  Shop — Some  Smithy  Appliances 
(by  A.  Livingstone  Oke) — Emergency  Backing-block — Coke  Furnace  for 
Heating  Drills  (by  Claude  T.  Rice) — Joplin  Steel-sharpening  Kinks  (by 
Claude  T.  Rice) — Sharpening  Machine-steel  by  Hand  (by  Emory  M.  Mar- 
shall)—Tempering  Hand-Drill  Steel  (by  Albert  G.  Wolf)— U-bolt  Bending 
Tool  (by  Dan  Fields) — Compressed-air  Jet  for  Cleaning — Devices  for  Bend- 
ing Plates  (by  Claude  T.  Rice) — Homemade  Timber-framing  Plant  (by  Frank 
M.  Leland) — Pipe  Rack — Carbide  Container  and  Measurer  (by  E.  W.  R. 
,  Butcher) — Changing  Dipper  Teeth  on  Steam  Shovels  (by  Clarence  M. 
Haight) — Grade-board  (by  L.  B.  Pringle) — Track  Connections — Rigid  Track- 
Connection  (by  E.  C.  Kingston) — Backing  Block  (by  L.  B.  Pringle)— 
Cooler  for  Drinking  Water  (by  E.  W.  Durfee) — Elevating  Guy  Lines  (by 
L.  E.  Ives)— Arc-Light  Tower. 

CHAPTER  II 

EXPLOSIVES 35 

Mammoth  Blasting  by  Electricity  (by  E,  Hibbert) — Sinking  with  Delay- 
action  Fuses  (by  W.  V.  DeCamp)— Blasting  Box  for  Sinking — Electric 
Blasting  with  Dry  Battery  (by  C.  Carleton  Semple) — Fuse-cutting  Table 
(by  Herbert  Oates) — Fuse-cutting  Bench  (by  S.  R.  Moore) — Powder  Chutes 
for  Openpits  (by  B.  M.  Concklin) — Bag  for  Carrying  Dynamite  (by  W.  R. 
Hodge) — Electric  Heating  for  Primer  House  (by  E.  P.  Kennedy) — Magazine 
for  Storing  and  Thawing  (by  Claude  T.  Rice) — Suitable  Powder  Magazines — 
Electric Powder-thawer Underground  (by  A.  J.Hewitt) — Hot-water  Powder 
Heater — Manure  Powder-thawer — Safety  Priming  Device  (by  William  W. 
Jones) — Blasting  Bulletin  Board — Form  for  Missed-hole  Reports  (by  B.  H. 
Smith) — Neutralizing  Blasting  Fumes  (by  W.  H.  Mawdsley). 

CHAPTER  III 

ROCK  DRILLS '.    .    .    .   58 

Drilling  Mesabi  Gopher  Holes — Cutting  Mass  Copper — Machine-driven 
Auger  for  Soft  Ground — Removing  Broken  Drill  from  Hole  (by  George  E. 
Addy) — Pneumatic  Drill-column  (by  Sven  V.  Bergh) — Tripod  for  Handling 

vii 


viii  CONTENTS 

PAGE 

Long  Drill-steel  (by  Le  B.  Reifsneider) — Simple  Machine  Bar — Steady  Tri- 
pod Set-up  on  Loose  Rock — Steadying  Leg  for  Rock-drill  Bars — Wedged 
Arm  for  Drill  Columns  (by  R.  A.  Rule) — Wedged  Drill-column  Collar  (by 
R.  A.  Rule) — Copper  Range  Drill  Column — Handling  Drill  Steel  at  the 
Quincy  Mine  (by  L.  Hall  Goodwin) — Repairing  Worn  Clamp  (by  George 
E.  Addy) — Drill  Tester  for  the  Shop — Failure  and  Heat  Treatment  of  Drill 
Steel  (by  Sven  V.  Bergh). 

CHAPTER  IV 

SHAFTS  AND  RAISES 80 

Shaft  Timbering  in  Minnesota  Iron  Mines  (by  L.  D.  Davenport) — Cage  and 
Bucket  for  Sinking  (by  Claude  T.  Rice) — Blasting  Irons  for  Shaft  Sets — 
Trolleys  for  Sinking  Incline  Shafts— Hinge  for  Shaft  Doors  (by  Clinton  P. 
Bernard) — Sinking  an  Untimbered  Shaft — Hanging  Bracket  for  Shaft  Plat- 
form— Aligning  Concrete  Forms  in  Shaft  (by  Robert  H.  Dickson) — Setting 
Timbers  in  Vertical  Shafts  (by  C.  W.  Macdougall) — Light  Shaft  Timbering 
(by  Harold  A.  Linke)— Diagonal  End  Plates,  Inclined  Shaft  (by  G.  A.  Denny) 
— Man  way  and  Skipway  Door — Inclined  Shaft  for  Timber  (by  L.  D.  Daven- 
port)— Unwatering  and  Equipping  Untimbered  Shaft  (by  Douglas  Muir) — : 
Concrete  Lining  of  the  Kingdon  Shaft  (by  Charles  B.  Eades  and  F.  E.  Calkins) 
— Concreting  the  Junction  Shaft  (by  Robert  H.  Dickson) — Rectangular  Con- 
crete Shaft  Lining — Raising  and  Enlarging  Negaunee  No.  3  Shaft — Steel 
and  Concrete  Lining  at  Palms  Shaft — Unit  Sets  of  Reinforced  Concrete — 
Relining  the  Hamilton  Shaft — Unit  Concrete  Sets  from  Central  Factory  (by 
L.  D.  Davenport) — Gunite  Casing  on  Wood  Shaft  Lining  (by  Stephen  Royce) 
— Concreting  Methods  in  Copper  Range  Shafts — Concrete  Collar  for  Mohawk 
Shaft — Concrete  Shaft  Collar  at  the  Wolverine — Concrete  Drop  Shaft  (by 
Claude  T.  Rice)— Concrete  Stringers  for  Incline  Tracks  (by  Claude  T.  Rice) 
— Concrete  Stringers  in  Steep  Inclines — Cushion  Blocks  on  Concrete  Skip- 
roads  (by  R.  B.  Wallace) — Cutting  Station  and  Pocket  in  Ore  (by  L.  D.  Daven- 
port)— Underground  Crushing  and  Loading  Arrangements  (by  Albert  E. 
Hall) — Debris  Hoppers  under  Hoisting  Compartments — Spillage  and 
Sinking  Pocket  (by  Albert  E.  Hall) — Concrete  Hoisting  Pocket — Concrete 
Shaft  Station,  Wolverine  Mine  (by  Claude  T.  Rice) — Wood,  Steel  and  Con- 
crete Station  (by  Claude  T.  Rice) — Concrete  Station  at  Champion  Mine- 
Scaffolding  in  an  Untimbered  Raise  (by  Frank  C.  Rork) — Five-hole-cut 
Raising  Method  (by  H.  H.  Hodgkinson) — Draining  Watercourses  in  Chutes 
(by  Edward  P.  Scallon) — Wood  and  Iron  Pipe  Ladder — Steel  and  Wood  Lad- 
der (by  Harold  A.  Linke)— Portable  Steel  Ladder  (by  L.  O.  Kellogg)— Pipe 
and  Angle  Ladder  (by  Edward  S.  Wiard) — Wood  vs.  Steel  Mine  Ladders 
(by  George  E.  Collins) — Isabella  Knockdown  Iron  Ladder  (by  Leo  H.  P. 
Kneip) — Method  of  Hanging  Ladders — Vertical-shaft  Steel  Stairway. 

CHAPTER  V 

DRIFTING •   • 177 

Driving  the  Sheep  Creek  Tunnel — Leyner  Drilling  Rounds  (by  Charles  A. 
Hirschberg) — Drift  Round  in  Flat  Sediments — Rapid  Drifting  by  St. 
Joseph  Lead — Drifting  with  a  Stoper  (by  G.  E.  Wolcott) — Recording  Mine 
Timbering  (by.  John  T.  Fuller) — Mesabi  Underground  Turn  Timbering — 
Building  Dry  walls,  Sudbury  District  (by  Albert  E.  Hall). 


CONTENTS  ix 

CHAPTER  VI 

PAGE 

STOPING 199 

Sloping  at  the  North  Star  Mine  (by  L.  O.  Kellogg) — Methods  and  Costs, 
Mother  Lode  Mine,  B.  C.  (by  E.  Hibbert) — Stoping  Methods  at  the  Golden 
Cross  Mine  (by  Andrew  W.  Newberry) — Mining  a  Pillar  of  Magnetite — 
Top-set  Slicing  on  the  Mesabi  Range  (by  L.  D.  Davenport) — Successful 
Top-set  Slicing  (by  Pomeroy  C.  Merrill) — Removing  Ore  under  Timbered 
Drift  (by  H.  H.  Hodgkinson) — Square-set  Timbers  for  Soft  Iron  Ores  (by  L. 
D.  Davenport) — Square-set  Framing  at  Butte — Square-set  Timbering 
at  Switches  (by  Frederick  W.  Foote) — Supporting  Back  While  Drawing 
Shrinkage  Stope  (by  H.  H.  Hodgkinson) — Top-slice  Timbering  at  Bingham 
(by  D.  W.  Jessup) — Hook  and  Staple  for  Staging — Building  High  Stages  with 
Ladders — Hook  for  Hauling  Timbers — Concrete  Bulkheads  for  Pillar  Ex- 
traction (by  Temple  Chapman) — Sand  Filling  at  Cinderella  Consolidated — 
Bore-hole  System  of  Sand  Filling — Bulkheads  for  Hydraulic  Filling — 
Conveyor  Belts  for  Distributing  Filling — Sconces  for  Holding  Candles — Ore 
Chutes  of  Sheet  Steel — Chute  Conveyor. 

CHAPTER  VII 

TIMBER  STRUCTURES 256 

Improved  Type  of  Ore  Bin  (by  Wilbur  E.  Sanders) — Bin  with  Compromise 
Bottom — A  700-ton  Ore  Bin  of  Logs  (by  W.  L.  Kidston) — Round-timber 
Bin  with  Novel  Emptying  System  (by  E.  S.  Shaw) — Development  of  Chute 
and  Gate  (by  Albert  E.  Hall)— Ore-chute  Side  Pocket  (by  Lewis  B.  Pringle) 
— Bulldozing  Chute  and  Underswung  Gate  (by  G.  J.  Jackson) — Substantial 
Ore  Chute  (by  H.  H.  Hodgkinson) — Chute  for  Loading  Car  from  Skip  (by 
W.  W.  Shelby) — Hanging  Chutes  (by  L.  D.  Davenport) — Concrete  Storage 
Chutes  in  Stopes — Chute  Reinforced  with  Angles  (by  Albert  G.  Wolf) — 
Quincy  Rockhouse  Loading  Chutes  (by  L.  Hall  Goodwin) — Underswung 
Gate  (by  J.  R.  Thoenen) — Supporting  Sliding  Gate  and  Lever — Pneumatic 
Underswung  Arc  Gate  (by  J.  R.  McFarland) — Air-lift  Finger  Chute  Gate — 
Underswung  Rack-operated  Arc  Gate  (by  Walter  R.  Hodge) — Safety 
Lever  for  Arc  Gate  (by  E.  W.  R.  Butcher) — Hydraulically  Operated  Skip 
Pockets  (by  Clarence  M.  Haight) — Handcock  Skip  Pockets  (by  Claude 
T.  Rice) — Emergency  Ore  Gate  (by  L.  D.  Davenport) — Headframe 
with  Guy-rope  Bracing — A-type  Timber  Headframe  (by  G.  A.  .Denny) 
— Concrete  Headframe  with  Fleeting  Device  (by  L.  O.  Kellogg) — 
Derrick  for  Sinking  557  Feet — Small  Four-post  Headframe  (by  H.  L. 
Botsford) — Reversible  Temporary  Headframe  (by  P.  V.  Burgett) — Tri- 
pod Headframe  (by  G.  E.  Le  Veque) — Prospecting  Headframe  with  Auto- 
matic Dump  (by  Charles  Mentzel) — Substitute  for  Small  Headframe  (by 
Walter  R.  Hodge)— Turn-sheave  Types  (by  Floyd  L.  Burr)— Turn-sheave 
Location  and  Support  (by  C.  R.  Forbes) — Turn  Sheaves  at  the  Lake  Mine  (by 
Karl  A.  May) — Tabulation  of  Trestle  Bent  Dimensions  (by  Clinton  Kimball) 
— Typical  Coal  Trestles — Post  and  Cap  Joint  for  Dumping-trestle — Wood 
Trestle  for  Motor  Tramming — Permanent  Stockpile  Trestle  of  Wood  (by 
Oscar  Gustafson) — Raising  Trestle  without  Ginpole  (by  R.  B.  Wallace) — 
Erecting  Trestle  Bents  with  Cableway  (by  A.  Livingstone  Oke) — A  Built- 
up  Ginpole  (by  A.  Livingstone  Oke) — Ginpole  of  10-in.  Pipe — Handling 
Stack  with  a  Ginpole  (by  A.  Livingstone  Oke) — Substructure  of  Wooden 


x  CONTENTS 

PAGE 

Water  Tank — Surface  Steam-line  Supports — Simple  Guyed  Derrick  (by 
H.  L.  Botsford) — Dipping  Tank  for  Mine  Timber  (by  L.  O.  Kellogg). 

CHAPTER  VIII 

HOISTING,  LOWERING,  TRANSPORTING •.    .    .    .   324 

Cableway-and-carrier  Bucket  Hoist  (by  R.  B.  Wallace) — Otis  Elevator  Mine 
Hoist  (by  L.  E.  Ives) — Chain-driven  Convertible  Hoist  (by  E.  E.  Carter) — 
Balancing  Dummy  in  Inclined  Shaft  (by  L.  Hall  Goodwin) — Fleeting 
Device  for  Hoist  with  Conical  Drums  (by  F.  H.  Armstrong) — Automatic 
Skip  Recorder — Go-devil  Incline  Plane — Improvement  in  Underground 
Trolley  Conveyors  (by  E.  M.  Weston) — Hoisting  over  a  Summit  (by  Frank 
C.  Rork) — Evolution  of  an  Electric  Signal  System  (by  George  A.  Packard)— 
Simple  Return  Signal  System  (by  H.  R.  Wass) — Electric  Signal  System,  Ar- 
gonaut Mine  (by  R.  S.  Rainsford) — Bare-wire  Electric  Signal  System — 
Gravity-release  Electric  Signal  Box  (by  W.  R.  Hodge) — Locked  Signal 
System  (by  H.  H.  Hodgkinson) — Bell-Wire  Arrangement  in  Sinking  (by 
Clinton  P.  Bernard) — Warning  Bell  for  Topman  (by  Harold  A.  Linke) — 
Automatic  Light  Switch  for  Electric  Tramming  (by  L.  O.  Kellogg) — Test-pit 
Windlass  (byL.  D.  Davenport) — Windlass  for  Single-hand  Sinking  (by  Albert 
G.  Wolf) — Device  for  Handling  Prospecting  Bucket  (by  Thomas  M.  Smither) 
— Lowering  in  Balance  through  Timber  Shaft — Lowering-windlass  for  Tim- 
ber Shaft  (by  L.  D.  Davenport) — Joplin  Type  of  Horse  Whim — Rope 
Idlers  for  Incline  Shaft — Roller  of  Pipe — Roller  of  Pipe  and  Wheels — 
Rope  Guide  to  Foot  wall  Sheaves  (by  Clarence  M.  Haight) — Substitute 
for  Rollers  in  Incline  (by  H.  H.  Hodgkinson) — Sheave-wheel  Lining  (by  G. 
L.  Sheldon) — Reversing  Rope  on  Single-drum  Hoist  (by  R.  S.  Schultz,  Jr.) 
— Reversing  Rope  with  Single  Coil  (by  Joseph  Hocking) — Reversing  Rope, 
Using  Power  of  the  Hoist  (by  C.  M.  Rasmussen) — Lubricating  Box  for 
Horizontal  Hoisting  Rope  (by  R.  B.  Wallace) — Tool  for  Bending  Rope  Wires 
in  Socket  Connection  (by  Joseph  Goldsworthy) — Single-screw  Wire-rope 
Clip  (by  A.  Livingstone  Oke) — Drag  Scraper  for  Handling  Dump  (by 
Frederick  W.  Foote) — Single-track  Cableway  (by  E.  Praetorius) — Single- 
track  Cableway  (by  Herbert  K.  Scott) — Loading  Derrick  at  Shaft  Collar  (by 
Clarence  M.  Haight) — Device  to  Stop  Whirling  Bucket. 

CHAPTER  IX 

SHAFT  CONVEYANCES 371 

Drop-bottom  Cage — Cage  with  Munzner  Safety  Catches — Four-deck 
Shaft-repair  Cage  (by  Albert  B.  Pedersen) — Ambulance  Cage  (by  L.  D. 
Davenport) — Latch  for  Holding  Car  on  Cage — Releasing  Hook  for  Cage 
Testing — Combination  Cage  and  Skip — Light  Skip  for  65°  Incline — Rear- 
dumping  Skip-car  (by  L.  O.  Kellogg) — Skip  Bail  Lock  and  Release  (by  S.  S. 
Jones) — Bailer  for  Winze  (by  S.  A.  Worcester) — Self-discharging  Inclined 
Bailing  Tank  (by  M.  G.  Sohnlein) — Double  Landing  Chairs — Chairs  for 
Drop-bottom  Cages — Skip  Dog  for  Inclined  Shaft  (by  Walter  R.  Hodge) — 
Angove  Skip  Dump— Adjustable  Skip-dump  Plate  (by  W.  C.  Hart)— Com- 
pressed-air Dump  Control  (by  J.  R.  McFarland) — Skip  and  Man-cage 
Transfer  (by  Walter  R.  Hodge)— Double  Skip-changing  Carriage  (by 
William  Hambley  and  Albert  E.  Hall)— Skip  Transfer  at  Incline-shaft 


CONTENTS  xi 

PAGE 

Collar  (by  Arthur  C.  Vivian)— Device  for  Holding  Skip  Rope  (by  L.  Hall 
Goodwin) — Joplin  Ore  Buckets — Bucket  for  Lowering  Drill  Steel  (by  Evans 
W.  Buskett)— Man  Platform  and  Bucket  Crosshead  (by  E.  M.  Hobart)— 
Rapid  and  Safe  Bucket  Connection  (by  Joseph  Goldsworthy) — Joplin 
Method  of  Dumping  Buckets — Device  for  Bucket  Dumping  (by  J.  R. 
McFarland) — Automatic  Bucket  Tipple  (by  D.  A.  Cavagnaro) — Bucket- 
dumping  Device  (by  Harold  A.  Linke) — Automatic  Water  Bucket  Dumper 
(by  Algernon  Del  Mar) — Dumping  Arrangement  in  Sinking  (by  L.  D. 
Davenport) — Sliding  Chute  for  Sinking  (by  L.  D.  Davenport). 

CHAPTER  X 

CARS 413 

Doe  Run  Mine  Car — Round-bottom  Car — Heavy  End-dump  Car  (by  H.  L. 
Botsford) — Copper  Range  Car  (by  Claude  T.  Rice) — Desloge  Car — Two 
Sublevel  Cars  (by  H.  L.  Botsford)— Pickands- Mather  Sublevel  Car- 
Federal  Gable-bottom  Car — Double-truck  Gable-bottom  Car — Middle- 
dump  Mine  Car  (by  W.  W.  Shelby) — Red  Jacket  Car — End-dumping  Stock- 
pile Car  of  Wood  (by  E.  W.  R.  Butcher) — Surface  Tram  Car — Rack-and- 
pinion  Front-rotating  Dump — Simple  Cradle  Dump  (by  Claude  T.  Rice) — 
Tipple  for  Seven-car  Train  (by  J.  R.  McFarland)— Tipple  for  Three- 
ton  Car — Spear-type  Dump — Sublevel  Car  Dump  (by  L.  D.  Davenport) — 
Combined  Transfer  and  Dump  Car — Car-transfer  System  in  Rockhouse — 
Car  for  Tramming  Drill  Steel — Skip  Car  for  Flat  Grades — Roller  Barrow 
— Truck  for  Lowering  Timber — Car  Wheels  for  Sprag  Braking — Device 
for  Retarding  Speed  of  Cars  (by  John  T.  Fuller) — Lever  and  Lock  for 
Side-dump  Car — Latch  for  Holding  Car  During  Loading — Car-bottom 
Straightener. 

CHAPTER  XI 

TRACK 444 

Track  Work  in  a  Minnesota  Mine  (by  E.  W.  R.  Butcher)— Tracks  for 
Loading  Station — Economical  Incline  Track  Arrangement — Track  Spreader 
and  Guard-rail  Bracket — Track  Curves  in  Top-slice  Rooms — Convenient 
Grade-stick  (by  Edward  H.  Orser) — Angle-iron  Track  Gage — Bending 
Rails  with  Screw-jack  (by  A.  Livingstone  Oke) — Notched-log  Rail  Bender 
(by  Charles  F.  Spaulding) — Rail  and  Tie  Holder — Switches  and  Crossings 
(by  D.  W.  Jessup) — Treadle-operated  Switch  (by  A.  H.  Bromly) — Tem- 
porary Crossover — Turnout  for  Narrow  Drift  (by  Albert  G.  Wolf) — 
Cheap  and  Satisfactory  Turntable  (by  L.  O.  Kellogg). 

CHAPTER  XII 

SAFETY  AND  SANITATION 463 

Safety  Alarm  for  Slack  Hoisting  Rope — Electric  Indicator  for  Hoist  Re- 
verse— Safety  Top  for  Incline  Top — Car  Catch  at  Incline  Top — Light  Safety 
Crosshead  (by  Roy  Marcellus) — Homemade  Safety  Crosshead  (by  Lowe 
Whiting)— Bucket  Dump-hook— Safety  Bucket  Hooks  (by  F.  C.  Rork)— 
Sliding  Chain  Gates  on  Cage  (F.  H.  Armstrong) — Lifting  Guards  for  Shaft 
Collar — Safety  Bonnet  for  Shaft  Opening  (by  E.  H.  Edyvean) — Folding 
Gate  Across  Shaft  (by  W.  H.  Jobe)— Hinged  Shaft  Bar— Swinging  Shaft  Gate 


xii  CONTENTS 

PAGE 

of  Iron  (by  W.  H.  Jobe) —  Handy  Gate  Latch — Protective  Combing 
for  Manway  Top — Safety  Door  for  Chute  Top  (by  H.  H.  Hodgkinson) — 
Automatic  Gong  for  Underground  Motor — Hanging  Troughs  for  Protect- 
ing Trolley  Wires  (by  Claude  T.  Rice)— V-Shaped  Trough  for  Trolley 
Wire  (by  Allen  H.  Foster) — Trolley- Wire  Troughs  for  Uniform  Height 
of  Back — Trolley- Wire  Protection  of  Round  Lagging  (by  W.  H.  Jobe) — 
Safety  Hand  Grip  for  Car  (by  H.  H.  Hodgkinson) — Shoeing  Mean  Mules — 
New  Type  of  Copper  Queen  Change  House — Change  House  with  Swim- 
ming Pools  (by  A.  SH.  Sawyer) — United  Verde's  New  Change  House — 
Homestake  Two-story  Change  House — Sanitary  Underground  Latrine 
(by  W.  B.  Hambly  and  A.  E.  Hall)— Septic  Tank  for  Underground  Latrine 
(by  H.  G.  Pickard) — Concrete  Latrine  at  the  New  United  Verde — Septic 
Tanks  at  Clarkdale,  Arizona— First-Aid  Bandage  Roller  (by  E.  W.  R. 
Butcher) — Resuscitation — Underground  Stretcher — Fire-Fighting  Pipe 
Lines  at  Mount  Morgan  (by  B.  Magnus) — Sanitary  Fountain  Made 
from  Cask  (by  E.  C.  Carter)— Home-made  Shower  Bath  (by  E.  W.  R. 
Butcher) — Removable  Chute-spray. 

CHAPTER  XIII 

DRAINAGE  AND  VENTILATION 504 

Unwatering  Shaft  with  Horizontal  Turbine  Pumps  (by  L.  C.  Moore) — 
Economical  Pump  Arrangement  (by  Howard  S.  Lee) — Home-made  Hand 
Pump — Hand-controlled  Compressed-air  Pumping  Barrel  (by  Arthur  O. 
Christensen) — Cast-steel  Pump  Valve — Suction  for  Station  Pump  (by 
H.  L.  Botsford) — Combination  Pump  and  Air  Lift — Air  Lifts  for  Shaft  Un- 
t  watering  (by  Arthur  O.  Christensen) — Six-inch  Pipe  for  Air-lift  Sump 
'  (by  M.  J.  McGill)— Built-up  Iron  Water  Door  (by  R.  R.  Heap) -^Cast-iron 
Door  for  Mine  Water  (by  H.  Beard)— Concrete  Bulkhead  under  200-lb. 
Head — Plugging  Water  Channels  into  Mine  (by  J.  E.  Reno) — Pressure  Venti- 
lation in  Cripple  Creek  (by  S.  A.  Worcester) — Automatic  Door  for  Ventilation 
Control  (by  H.  S.  Gieser) — Ventilating  Pipes — Tunnel  and  Level  Ventilation 
— Adobe  Stove  for  Tunnel  Ventilation  (by  T.  Swift) — Charcoal  Pot  for  Venti- 
lating Shaft. 

INDEX  534 


DETAILS  OF  PRACTICAL  MINING 

i 

SURFACE  PLANT  AND  OPERATIONS 

Buildings — Power  Plant — Shop  Appliances — Handling  Supplies — Steam- 
shovel  Work — Miscellaneous  Notes 

BUILDINGS 

Sectional  Portable  Camp  Buildings  (By  George  S.  Rollin). — The 
design  and  erection  of  the  buildings  for  drilling  camps  are  frequently 
left  to  the  discretion  of  the  foreman  and  in  most  cases  when  a  job  is 
completed,  the  buildings  are  a  total  loss,  not  being  of  a  type  which  can 
be  moved.  In  order  to  be  able  to  use  such  buildings  over  again,  plans 
for  portable  sectional  buildings  here  illustrated  were  drawn  in  the 
case  of  a  large  exploration  company.  By  the  use  of  such  standard  sec- 
tions, buildings  of  any  necessary  dimensions  and  proportions  can  be  had ; 
they  can  be  readily  assembled  and  torn  down;  they  become,  in  fact,  part 
of  the  regular  drilling  equipment,  shipped  with  the  machinery  and  re- 
turned therewith  to  the  central  warehouse.  The  net  result  is  a  consider- 
able saving  in  time  and  material.  The  chief  buildings  to  be  provided 
for  are  the  bunkhouse,  the  eating  house,  the  drilling  shed,  and  the  dia- 
mond-setting shed.  The  walls,  roofs  and  floors  are  divided  into  panels 
made  of  2  X  4-in.  framing  with  1-in.  sheathing.  The  height  and  width 
are  thus  determined ;  the  length  can  be  varied  to  suit  conditions.  Special 
sections  provide  for  doors,  windows,  corners,  ends,  etc.  The  whole 
building  is  covered  with  a  tar  felt  when  erected. 

The  principal  building,  Fig.  1,  is  made  20  ft.  wide  with  an  8-ft. 
wall.  Into  this  there  enter  eight  different  sections.  In  case  new  sec- 
tions have  to  be  made,  the  man  in  charge  of  the  establishment  of  the 
camp  is  given  an  erecting  sheet  shown  at  9,  of  which  one  is  prepared 
for  each  of  the  four  types  of  buildings  mentioned.  This  shows  the 
layout  of  the  building  and  by  its  aid  the  necessary  sections  can  be  ordered 
and  all  supplies  and  materials  specified  exactly. 

The  instructions  which  accompany  the  erecting  sheet  are  as  follows: 

Determine  first  the  number  and  position  of  doors  and  windows  desired. 
Mark  their  sections  on  the  erecting  sheet  by  the  proper  number,  thus 
indicating  where  the  sections  will  appear  in  the  assembled  building. 

1 


DETAILS  OF  PRACTICAL  MINING 


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t    J — SECTIONAL  CAMP  BUILDING,   PANELS  SEPARATE  AND  ASSEMBLED. 


SURFACE  PLANT  AND  OPERATIONS,  3 

The  sheet  will  then  show  the  number  of  plain  wall  sections,  the  window 
sections,  the  door  sections  and  the  corner  end  sections  entering  into  the 
building.  In  the  same  way  determine  and  mark  on  the  sheet  the  end 
roof  sections  and  inside  roof  sections,  designating  those  to  be  provided 
with  stove-pipe  holes,  and  the  floor  and  gable  sections.  You  can  now 
turn  over  to  the  carpenter  the  construction  sheets,  1  to  8,  and  specify 
how  many  of  each  section  are  required.  The  erecting  sheet  should 
accompany  these  detail  sheets  as  an  aid  to  the  carpenter. 

To  erect  the  building:  Cut  first  the  five  sills  from  neighboring  trees 
and  flatten  them  on  one  side  at  least;  lay  them  lengthwise  of  the  building 
and  level  the  flat  sides  with  a  spirit  level.  Splice  2  X  6-in.  by  12-ft. 
pieces  for  the  floor  beams  and  lay  them  across  the  sills  as  shown,  leveling 
both  ways.  Lay  the  floor  sections,  8,  lengthwise  of  the  camp  and  nail 
them  with  a  few  short  nails,  preferably  finishing  nails,  at  each  end.  This 
completes  the  floor. 

Set  up  the  wall  sections,  1,  2,  3  and  7,  in  their  proper  positions  as 
outlined  on  the  erecting  sheet.  Bolt  them  together  in  all  cases;  if 
bolts  are  not  at  hand,  wait  for  them,  and  never  nail.  Square  up  the  walls. 
Put  stays  across  between  the  walls  at  every  second  section  to  keep 
the  walls  from  spreading  when  the  roof  is  put  on.  For  this  purpose,  use 
2  X  4-in.  by  20-ft.  pieces,  or  2  X  6-in.  by  12-ft.  pieces  spliced.  The  stays 
may  be  fastened  to  the  wall  sections  just  below  the  top  by  spiking  with  40- 
penny  nails,  three  to  each  end.  Bind  the  tops  of  the  four  sides  with 
2  X  4-in.  pieces.  If  necessary  to  break  these  along  the  side  walls,  see 
that  the  break  comes  over  the  center  of  a  wall  panel.  See  that  the 
binding  2  X  4-in.  pieces  come  exactly  over  the  2  X  4-in.  pieces  forming 
the  tops  of  the  wall  panels.  Fasten  with  two  40-penny  nails  spiked  to 
each  panel.  The  ends  must  measure  20  ft.  over  all,  in  order  that  the 
roof  section  may  fit  easily. 

The  gable  end  sections,  4,  should  be  next  erected.  They  are  to 
be  bolted  on  with  63^-iri.  bolts;  for  this  purpose,  bolt-holes  will  have  to  be 
bored  through  the  2  X  4-in.  pieces  forming  the  wall  top,  so  as  to  cor- 
respond with  the  bolt-holes  already  in  the  gable-bottom  piece.  Next 
nail  along  the  top  of  the  side  wall  the  1  X  4-in.  strip,  shown  in  9,  under 
the  eaves  and  so  marked;  it  should  be  of  good  material  and  should 
project  about  2-in.  above  the  2  X  4-in.  pieces  so  as  to  serve  for  the  lower 
crosspieces  of  the  roof  sections  to  butt  against.  It  may  be  necessary 
to  plane  off  a  little  of  the  top  of  this  strip  so  that  the  lower  crosspieces 
of  the  roof  sections  will  rest  on  the  side  walls  and  not  be  held  up  by  the 
projecting  portions  which  form  the  eaves,  resting  on  the  1  X  4-in. 
strip. 

The  roof  is  next  to  be  put  on.  Begin  at  one  end,  raising  two  opposite 
end  sections,  5.  The  1-in.  board  used  to  face  the  outside  2  X  4-in. 


4  DETAILS  OF  PRACTICAL  MINING 

piece  of  the  roof  section  should  be  set  flush  with  the  outside  boards  of 
the  gable  section  and  then  the  inside  edge  of  the  roof  section  will  be  flush 
with  the  edge  of  the  side  wall  section  on  which  the  lower  end  rests.  In 
this  way  the  roof  and  wall  sections  will  correspond  for  the  length  of  the 
building.  The  inside  roof  sections,  6,  are  next  raised  in  pairs  and  are 
bolted  together  on  the  sides  with  the  one  bolt,  as  shown.  Care  must  be 
taken  to  get  the  stove-pipe  section  in  the  right  position.  The  lower 
crosspieces  of  these  sections,  as  stated,  butt  against  the  1  X  4-in.  strip 
along  the  top  of  the  side  walls.  Add  the  inside  sections  until  the  end  of 
the  building  is  reached,  when  a  pair  of  end  sections  must  be  put  on.  The 
completed  roof  may  have  four  cracks  between  the  2  X  4-in.  pieces  of  its 
end  sections  and  the  top  2  X  4-in.  pieces  of  the  gable  sections.  These 
may  be  covered  with  a  board  5  to  8  in.  wide,  fitted  as  shown.  The  whole 
building  is  then  to  be  covered  with  tar  felt  held  on  with  lath.  With  the 
dimensions  shown,  the  floor  sections  will  not  fit  for  a  building  over  four 
sections  long.  For  a  longer  building  it  is  advisable  to  cut  off  enough 
on  one  row  of  floor  sections  to  prevent  their  projecting  beyond  the  walls, 
as  a  projection  tends  to  allow  moisture  to  run  in  on  the  floor.  The 
cut  sections  can  be  put  next  the  door,  which  is  ordinarily  in  the  end 
of  the  building.  They  receive  there  the  most  wear  and  being  cheap 
can  be  discarded  as  worn  out  when  the  building  is  moved. 

On  each  erecting  sheet  is  given  a  list  of  supplies  and  equipment  as 
shown  in  the  table,  with  blank  spaces  where  the  number  or  quantity 
can  be  filled  in.  When  the  size  of  building  has  been  decided  upon,  the 
bill  of  materials  is  made  out  exactly  and  the  possibility  of  a  shortage  of 
material  is  thus  minimized. 

TABLE  OF  SPECIFICATIONS 

Windows— 12  X  24-in.  (2  lights) No. 

Stove-pipe  saddles  (22  X  24-in.  rise  4  in  8) No. 

Bolts,  K  X  4^-in No. 

%  X  5>^-in.  (usually  8) No. 

%  X  6>£-in.  (usually  8) No. 

Hinges No.  pr. 

Door  latches No. 

Nails,  40-penny Lb. 

10-penny Lb. 

shingle Lb. 

Tar  felt Rolls. 

Lath Bundles. 

Boards — 1  X  4  in Lin.  ft. 

Boards,  extra 

2  X  6-in.  by  10-ft No. 

2  X  4-in Lin.  ft. 

Inexpensive  Miners'  Dwellings  (By  P.  E.  Barbour). — One  board- 
ing house,  two  four-room  houses  and  three  two-room  houses,  in  accord-* 


SURFACE  PLANT  AND  OPERATIONS  5 

ance  with  the  illustrations  of  Fig.  2,  were  built  complete  at  the  Mont- 
gomery mine,  Candor,  N.  C.,  for  $1223.  The  buildings  were  of  plain 
boards,  battened  up  and  down,  and  the  rooms  inside  were  finished 
overhead  only.  The  sills  were  6  X  6  in.  and  the  corner  posts  4  X  4  in. 


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South  Elevation 

Boarding  house — Sills,  6  X  6  in.;  corner  posts,  4  X  4  in.;  studding, 
2  X  4  in.;  girts,  2  X  4  in.;  floor  joists,  2  X  8  in.;  sheathing,  1-in.  boards, 
vertical,  with  3-in.  battens.  Roofing 28-gage  V-crimp.  Ceiledinside 
overhead  only,  walls  left  rough.  Sash  made  to  slide,  no  weights  or 
cords  used. 


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Four-room  house — Sash,  6-light,  10  X  12 in. 
Doors,  2  ft.  Gin.  by  6  ft.  6  in^  Chimney,  4  ft. 
Roofing,  28-gage  V-crimp.  Shiplap  or  German 
siding.  Interior  ceiled  overhead  only.  Inside 
walls  left  rough. 


Two-room  house — Sash,  4  singles. 
Doors,  2  ft.  6  in.  by  6ft.  6  in.  Chim- 
ney, 4  ft.  Roofing,  28-gage  V-crimp, 
Siding,  shiplap  or  rough  boards  with 
battens.  Ceiled  overhead  only. 


FIG.    2. TYPES     OF     MINE     DWELLINGS     AT     THE     MONTGOMERY     MINE,    CANDOR,    N.    C. 


All  roofs  were  covered  with  28-gage,  V-crimped  roofing  and  painted. 
Lumber  cost  $12  to  $13  per  M  and  labor,  from  $1.25  to  $3  per  day. 
The  two-room  houses  were  for  negro  laborers;  the  other  dwellings  were 
for  whites.  Rent  at  the  rate  of  50  cts.  per  room  per  month  was  charged 
for  all  company  dwellings,  being  $1  for  the  negroes  and  $2  for  the 


6 


DETAILS  OF  PRACTICAL  MINING 


whites  per  month.     These  dwellings  were  good  enough  for  the  climate 
and  were  considered  desirable  by  the  dwellers. 

Ventilating  Bunkhouses  (By  George  S.  Rollin). — A  device  in 
logging  camps  for  maintaining  ventilation  in  the  bunkhouses  is  equally 
applicable  to  mining  bunkhouses.  The  stove,  Fig.  3,  is  usually  set 
near  the  center  of  the  building;  for  the  device  in  question,  a  secondary 
stove  pipe  is  erected  as  close  as  possible  to  that  of  the  stove,  beginning 
8  to  12  in.  above  the  floor  and  extending  through  the  roof;  it  is  provided 
with  a  damper.  In  one  corner  of  the  building,  a  hole  is  cut  through 
the  wall,  a  short  length  of  stove  pipe  inserted,  and  connected  with  an 
ell  to  a  downright  section.  This  latter  also  extends  to  a  point  8  to  12 


FIG.    3. ARRANGEMENT    OF    AUXILIARY   VENTILATING    PIPES. 

in.  from  the  floor.  The  pipe  next  the  stove  is  heated  and  tends  to  draw 
up  the  air,  thus  adding  to  the  amount  of  ventilation.  The  pipe  from  the 
outside  carries  the  air  to  a  point  near  the  floor,  so  that  direct  draft  is 
avoided,  and  the  incoming  air  is  also  somewhat  warmed  before  dis- 
charging into  the  room. 

POWER  PLANT 

Trench  and  Pipe  Feed -water  Heater. — A  simple,  yet  successful 
method  of  utilizing  the  exhaust  steam  from  hoisting  engines  to  heat 
feed  water,  is  shown  in  the  accompanying  drawing,  Fig.  4.  It  was 
designed  for  a  Mesabi  mine,  where  before  its  introduction  the  steam 
from  the  hoist,  as  is  usual  in  many  plants,  exhausted  into  the  air  through 


SURFACE  PLANT  AND  OPERATIONS  7 

a  small  boiler  used  as  a  preheater,  a  method  that  proved  most   un- 
satisfactory. 

A  trench  was  dug  from  the  shaft  to  the  boiler  house,  a  distance  of 
140  ft.,  open  to  the  atmosphere  at  the  shaft  end  through  a  Y.  The 
ditch  was  lined  with  concrete  and  covered  with  3-in.  planking,  28-gage 
corrugated  iron  and  1  ft.  of  dirt.  The  exhaust  steam  from  the  hoist 
discharges  into  the  conduit  at  the  engine  house  against  atmospheric 
pressure  and  passes  through  it  into  the  air  at  the  other  end.  The  water 
from  the  mine  in  a  3-in.  pipe  passes  from  a  sump  at  the  shaft  through 


Loose  -Dirt 

No.  25 

Corrugafed*^-^ 
Iron 


3  "Suction  pipe  to  boiler 
house  pump 

^ 


V'Plank 


£ 


\ICorruc 

i*^ 

"*io< 

^gy 

icrfed 
•ing  Rods 

•  &SUMP 
H, 

t       ^ 

> 

^ 


e. 


fc-^l 

§  'S& 


WATER  TANK 

CAP.  40,000  GAL       8 

from  Hoist 


j3  Steam  pi  petp  pump  in  mine  \  4  Suction  pipe  ' 

"]8  "Discharge  pipe  from  mine  into  sump         \  tank  to  pump 


8>" Discharge 
pipe  from 
mill 


SUMP 


FIG.    4. WATER    AND    STEAM    PIPES    IN    CONCRETE-LINED    TRENCH. 


the  conduit  to  a  300-gal.  per  minute  Prescott  feed-water  pump  in  the 
boiler  house.  It  is  picked  up  by  this  pump  and  forced  through  a  4-in. 
pipe  to  the  shaft  and  back  into  the  boiler.  The  temperature  of  the 
water  entering  the  boiler  is  about  180°  F.  in  contrast  with  110°  when 
the  old  method  was  used.  In  case  of  accident  to  the  underground 
pumps,  water  can  be  drawn  from  the  storage  tank  through  the  con-, 
nections  shown.  The  conduit  also  carries  a  2-in.  and  a  3-in.  steam 
pipe  to  the  mine  pumps.  The  company  using  this  method  figures  that 
it  has  saved  about  10  per  cent,  of  its  coal  consumption  without  adding 
any  upkeep  cost. 


8 


DETAILS  OF  PRACTICAL  MINING 


Timber  Foundations  for  Engines  (By  A.  Livingstone  Oke). — Some- 
times, for  reasons  of  economy  or  for  temporary  purposes,  it  is  necessary 
to  use  timber  for  the  foundations  of  small  engines,  such  as  hoists, 
pumps,  etc.,  and  Fig.  5  shows  one  method  which  gives  a  rigid  setting. 
In  the  example  shown,  several  feet  of  soft  soil  overlies  a  rock  bottom; 
in  such  cases  it  is  desirable  to  make  the  foundation  of  such  depth  that 
it  will  rest  directly  on  rock,  as  shown.  An  alternative  is  to  place 
long,  heavy  bearers  transverse  to  the  upper  framing  and  bolt  to  these, 
but  the  former  method  is  always  to  be  preferred.  It  is  particularly 
necessary  to  place  the  bolts  inclined  as  shown,  for  the  reason  that  end 
movement  of  the  foundation  tends  to  tighten  an  inclined  bolt,  while 
the  converse  is  true  with  a  vertical  one.  The  bolts  may  be  made 
jagged  at  their  bottoms  and  run  in  with  neat  cement,  sand  and  cement, 
or  sulphur. 


cement  \  \ 
or  sulphur 

FIG.  5. TIMBER  FOUNDATION  FOR  ENGINE  ANCHORED  TO  ROCK. 


Foundations  for  Prospecting  Machinery  (By  Horace  F.  Lunt) . — 
Timber  foundations  are  perfectly  satisfactory  if  properly  designed,  and 
if  they  are  not  intended  for  use  for  a  longer  time  than  the  life  of  the 
timbers;  this  period  will,  of  course,  vary  with  the  kind  of  timber  and  the 
conditions  under  which  it  is  used.  The  illustration,  Fig.  6,  shows  a 
timber  foundation  designed  for  a  6  X  8-in.  steam  hoist.  Its  essential 
feature  is  the  platform  between  the  sills,  on  which  sufficient  rock  and 
earth  is  piled  to  hold  the  hoist  steady.  A  foundation  of  similar  design 
but  of  heavier  (12  X  12-in.)  timbers  for  a  30-hp.  electric  hoist  has  been 
used  with  perfectly  satisfactory  results.  This  design  has  also  been  em- 
ployed, using  round  timbers  and  round  poles  in  place  of  the  plank  plat- 
form, the  upper  set  of  timbers  being  hewed  flat  to  receive  the  bedplate  of 
the  hoist.  Round  timbers  make  it  a  little  more  difficult  to  level  the 
foundation,  but  are  otherwise  just  as  good. 

In  building  such  a  foundation  the  following  notes  will  be  found  useful: 


SURFACE  PLANT  AND  OPERATIONS 


9 


The  holes  for  the  anchor  bolts  should  be  bored  %  in.  larger  than  the 
bolts,  in  order  to  allow  for  the  variations  of  the  bedplate  castings.  The 
holes  should  be  bored  after  the  timbers  are  framed  and  placed  in  position; 
otherwise  there  is  likely  to  be  difficulty  in  getting  the  bolts  through  them. 
The  lower  ends  of  the  anchor  bolts  should  rest  on  something  solid,  a 
good-sized  flat  rock  or  a  substantial  piece  of  timber,  so  that  they  cannot 
be  driven  down  out  of  reach  by  any  accidental  blow  before  the  hoist  is 
in  position.  The  upper  ends  of  these  bolts  should  project  far  enough 
through  the  holes  in  the  bedplate  to  permit  of  their  being  grasped  with 
a  pipe  wrench  in  case  they  turn  when  the  nuts  are  being  tightened.  If 
possible,  the  excavation  for  the  foundation  should  be  large  enough  for  a 


Bolts  20l  long  cast 
washers  arbotn  ends 


SIDE   ELEVATION 


END  ELEVATION 


FIG.    6.  -  TIMBER   FOUNDATION    FOR   HOISTING    ENGINE. 


man  to  get  down  into  it  and  tamp  under  the  mud  sills  after  it  is  all  put 
together.  Even  if  the  sills  are  leveled  carefully  at  the  start,  the  top  may 
be  found  out  of  level,  due  to  inequalities  in  the  timbers.  If  round 
timbers  are  used,  it  is  practically  impossible  to  level  the  foundation  until 
it  is  completely  assembled.  Setting  the  foundation  with  its  greatest 
dimension  parallel  to  the  line  from  the  hoist  to  the  shaft  gives  the  maxi- 
mum stability.  I  have,  however,  placed  the  sills  at  right  angles  to  this 
line,  where  circumstances  prevented  their  being  laid  the  other  way, 
making  them  somewhat  longer  in  proportion  to  the  rest  of  the  foundation, 
so  as  to  increase  the  area  of  the  platform  and,  therefore,  the  weight 
holding  the  foundation  in  place.  This  design  can  easily  be  adapted  to 
small  compressors  or  other  machines.  Where  a  belted  compressor  is 


10 


DETAILS  OF  PRACTICAL  MINING 


used,  a  satisfactory  construction  is  to  use  the  same  sills  as  a  base  for 
both  compressor  and  motor  foundations. 

Automatic  Belt  Tightener  (By  J.  R.  McFarland). — An  unusual 
automatic  belt  tightener  providing  a  new  use  for  worn-out  stoping  drills 
was  devised  by  C.  C.  Griggs,  superintendent  of  the  Uncle  Sam  Mining 
Co.,  at  Eureka,  Utah.  In  changing  a  straight-line  steam-driven  air 
compressor  to  motor-power  belt  drive,  the  pulley  of  the  compressor  was 
placed  on  the  shaft  between  the  two  narrow-rimmed  fly  wheels.  On 
account  of  the  proximity  of  the  cylinder,  the  pulley  had  to  be  smaller 
than  good  practice  would  allow.  The  necessity  of  having  the  belt  tight 
on  high  pressures  was  apparent.  A  wooden  frame  was  erected  about 
midway  of  the  belt.  On  each  of  the  perpendicular  posts  a  feed  cylinder 
from  a  worn-out  stoper  was  placed.  To  the  bottom  of  the  feed  pistons  a 


FIG.    7. ANCHOR    POSTS,   BOLTS    AND    YOKE. 

shaft  bearing  an  idler  was  attached  with  the  idler  bearing  directly  on  the 
belt.  The  tops  of  the  feed  pistons  were  connected  with  the  air  line  to  the 
receiver.  As  the  air  pressure  rises  in  the  receiver  and  the  strain  becomes 
greater  on  the  belt  with  an  increased  tendency  for  belt  slippage,  the  air 
pressure  working  on  the  stoper  feed  pistons  holds  the  idler  tightly  against 
the  belt  and  as  the  air  pressure  in  the  receiver  drops  the  tension  on  the 
belt  is  automatically  released. 

Hillside  Pipe-line  Anchor  (By  W.  R.  Hodge).— To  take  up  some 
of  the  weight  of  a  pipe  line  laid  on  the  surface  of  the  ground  and  pitching 
steeply,  the  arrangement  shown  here,  Fig.  7,  is  used.  Two  6  X  6-in. 
posts,  sunk  well  in  the  ground,  hold  each  a  %-in.  rod.  These  rods  have 
at  the  end  an  eye  through  which  they  are  bolted  to  a  yoke.  This  yoke 
encircles  the  pipe  to  be  supported.  The  yoke  is  made  in  two  parts  and 


SURFACE  PLANT  AND  OPERATIONS 


11 


is  drawn  up  snugly  about  the  pipe  by  means  of  two  j^-in.  bolts  set 
close  to  the  pipe. 

Cheap  Expansion  Joint  (By  Fred  D.  Smith). — For  installing  a  3-in. 
steam  line  800  ft.  long,  to  furnish  a  temporary  supply  of  steam  from  a 
distant  boiler  to  the  hoisting  works  at  the  Snow  Creek  mine,  the  usual 
expensive  expansion  joints  were  dispensed  with  and  in  their  stead 
"shears"  were  used,  made  of  the  same  size  pipe  as  the  main  line,  and 
so  called  because  as  the  line  expands,  the  mains  slide  past  each  other 
and  the  upright  nipples  A  become  crossed,  thus  appearing  as  shears. 

The  accompanying  drawing,  Fig.  8,  shows  the  arrangement  of  the 
device,  which  requires  five  nipples  and  six  ells.  The  nipples  B  and  C 
may  be  of  any  length,  however  short,  while  the  nipples  A  should  be  of 
a  length  proportionate  to  the  length  of  the  steam  line.  In  this  800-ft. 
pipe  line  the  nipples  A  were  made  about  30  in.  long.  No  strain  or 


FIG.    8. — EXPANSION   JOINT   OF   NIPPLES    AND    ELLS. 

tension  can  come  on  the  ells  since  the  nipples  can  all  turn  in  the  elbows. 
It  is  suggested  that  the  pipes  at  these  joints  should  be  put  together 
with  graphite  to  insure  easy  movements  of  the  nipples  in  the  elbows. 
Since  there  are  no  less  than  six  threads  on  which  these  turns  can  be 
accomplished,  there  is  little  or  no  danger  of  a  sufficient  turn  in  any  one 
elbow  to  open  the  joint  and  cause  leakage.  As  but  one  of  these  arrange- 
ments was  used  in  the  800-ft.  line,  the  movement  in  the  shears  amounted 
to  about  3  ft.  While  this  device  in  a  steam  line  in  a  shaft  has  no.t  been 
used  so  far  as  known,  yet  it  should  be  available  if  one  were  set  about 
every  100  ft.,  thus  requiring  probably  only  about  a  12-in.  length  in  the 
nipple  A. 

SHOP  APPLIANCES 

Variable -stroke  Air  Hammer  (By  J.  R.  McFarland). — At  the  Giroux 
Consolidated  Mines  Co.,  at  Kimberly,  Nev.,  an  air  hammer  for  the 


12 


DETAILS  OF  PRACTICAL  MINING 


blacksmith  forge  was  constructed  out  of  an  old  3j^-in.  rock  drill.  This 
is  usual  practice  but  the  delicate  control  of  which  the  hammer  is  capable 
warrants  its  description.  The  arrangement  is  patterned  after  the 
design  commonly  used  on  drill-steel  sharpeners  and  works  much  more 
satisfactorily  than  the  customary  throttle  valve  to  govern  the  opera- 
tion of  the  hammer.  With  a  throttle  valve  the  length  of  strokes  can- 
not be  varied  and  when  the  throttle  is  closed  the  hammer  and  piston 
drop  to  the  bottom  and  are  in  the  way.  With  the  improved  arrange- 
ment, shown  in  Fig.  9,  both  the  power  and  length  of  the  stroke  are  gov- 
erned by  a  small  rod  extending  through  the  front  end  of  the  valve  chest, 
hindering  or  releasing  the  valve.  The  rod  has  a  small  shoulder  on  the 
inside  to  prevent  its  coming  out  of  the  chest.  The  rod  on  the  outside 
end  fits  against  a  lever  with  a  spring  attached  to  one  end,  holding  back 
the  valve  when  at  rest  and  allowing  air  to  enter  in  front  of  the  cylinder 


Li-.i..j_nii  'pocj  Controling  Valve 


J,^ 


PIG.    9. ARRANGEMENT  OF  HAMMER  AND  VALVE. 

and  hold  the  piston  up  out  of  the  way.  As  the  handle  of  the  lever  is 
pulled  back  slowly,  the  air  is  first  allowed  to  enter  the  back  end  of  the 
cylinder  in  small  quantities  so  that  the  strokes  are  light  and  short,  the 
piston  being  reversed  immediately  after  the  reverse  port  is  passed. 
As  the  lever  is  pulled  farther  back  the  drill  gets  its  full  supply  of  air 
and  the  momentum  of  the  piston  gives  it  a  longer  stroke.  As  the  re- 
bound from  an  iron  anvil  is  greater  than  from  rock  a  rubber  buffer  is 
placed  in  the  back  head.  The  neck  of  the  piston  was  originally  1J£ 
in.  but  as  a  3-in.  square  hammer  is  used  the  neck  was  increased  to  2  in. 
The  end  of  the  piston  neck  .or  stem  has  a  beveled  fit  in  the  hammer. 
The  control  is  so  delicate  as  to  allow  a  piece  of  paper  to  be  picked  off 
the  anvil  by  the  hammer  without  the  hammer's  touching  the  anvil. 

Stand  for  the  Blacksmith  Shop. — A  handy  little  device  in  use  in  the 
blacksmith  shop  of  the  Sterling  Iron  &  Ry.  Co.  at  Lakeville,  N.  Y., 


SURFACE  PLANT  AND  OPERATIONS 


13 


is  shown  herewith,  Fig.  10.  It  serves  as  a  stand  for  resting  the  free 
end  of  long  drill  steel  in  process  of  being  sharpened  or  for  other  long  work 
on  the  anvil.  The  supporting  base  is  a  discarded  handwheel  such  as 
is  used  for  rack-and-pinion  chute  gates  or  for  car  brakes.  Into  the 
square  center  hole  is  fastened  a  short  piece  of  IJ^-in.  pipe.  In  this  is 
telescoped  a  piece  of  %-in.  round  iron;  this  is  riveted  through  a  hori- 
zontal piece  of  iron  bar  with  its  ends  turned  up,  on  which  the  work  can 
rest.  The  height  of  this  T-shaped  standard  can  be  adjusted  in  the  pipe 
stand  by  means  of  a  nail  thrust  through  a  hole  in  the  pipe  and  one  of 
several  holes  in  the  rod,  the  latter  spaced  about  3  in. 


FIG.    10. HOMEMADE  SHARPENING  REST  FOR  LONG  STEEL. 

Some  Smithy  Appliances  (By  A.  Livingstone  Oke). — The  accom- 
panying drawings,  Figs.  11,  12,  and  13,  illustrate  a  few  appliances 
in  the  smith's  shop  at  a  mine  in  British  Columbia.  A  circular  forge 
made  of  light  sheet  iron  is  shown  in  Fig.  11 ;  it  may  be  4  or  5  ft.  in  diam- 
eter. Air  is  supplied  by  a  large  pipe  a  few  inches  lower  than  the  top 
of  the  sheet  iron;  there  are  three  vents  shown  but  only  one  is  usually 
required,  except  for  big  heats.  A  sliding  rest  is  shown  at  the  back, 
consisting  of  a  single  piece  of  iron,  bent  to  a  U-shape,  the  two  longer 
limbs  passing  into  the  side  of  the  hearth  and  underneath  the  air  pipe. 
At  the  side  is  shown  a  swinging  arm  which  is  also  curved  horizontally 
to  lie  close  around  the  outside  of  the  hearth  when  not  in  use.  It  is 


14 


DETAILS  OF  PRACTICAL  MINING 


worth  noting  that  whenever  possible  the  air  pipe  at  the  side  should  be 
bent  over  and  taken  underneath  the  floor  level,  as  this  leaves  the  forge 
clear  all  around  for  working. 

A  small  furnace  for  heating  drill  steel,  which  is  inserted  from  both 


Sliding  Iron  J?esf 


FIG.    11. CIRCULAR  FORGE  WITH  RESTS  ATTACHED. 


1 

<fe-     ^"          > 

H 

Open'/ng  /5x4  "for 
pifff-ing  in  drills 

II 

s 

^ 

I 

••; 

^ 

y 

5        P 

7/j7Jr/i  1 1//'/// f'/f'f/fff /'/''''//'''''''/'////////////// /'////  '/'.•  r//':  rfS' 
FIG.    12. FURNACE  FOR  HEATING  DRILL  STEEL. 


FIG.    13. BACKING-BLOCK  OF  STEEL  RAIL. 

sides  in  the  openings  near  the  top,  is  shown  in  Fig.  12.  The  body  of  the 
furnace  consists  of  sheet  iron  riveted  to  two  rectangular  frames,  at  top 
and  bottom.  Inside  this  body  a  firebrick  lining  is  laid  and  carefully 
fitted.  The  bottom  of  the  furnace  proper  has  a  revolving  grate,  worked 
by  a  handle  at  the  side.  Below  the  grate  is  the  air-box,  which  also 


SURFACE  PLANT  AND  OPERATIONS 


15 


receives  the  ashes  and  from  which  they  are  discharged  through  the 
hinged  door,  held  up  by  the  links  as  shown.  There  is  a  slightly  conical 
cupola-top,  through  which  the  coke  may  be  added. 

A  simple  footing  or  backing  block  for  holding  drill  steel  up  to  the 
anvil  when  swaging  is  shown  in  Fig.  13.  It  consists  of  a  piece  of  20- 
or  30-lb.  rail,  bent  as  shown  and  laid  on  two  or  more  sleepers,  with 
suitable  notches  cut  in  it  to  receive  the  ends  of  the  drill  steel.  The  top 
of  the  rail  should  be  spiked  to  the  timber  under  the  anvil,  as  well,  to 
assist  in  holding  it  solidly  up  to  the  work. 

Emergency  Backing-block. — In  Fig.  14  is  shown  a  backing-block 
made  of  a  rail  in  somewhat  the  same  manner  as  that  just  described  but 
with  the  position  of  the  rail  reversed.  Except  for  being  somewhat  light, 
it  answered  the  purpose  as  well  as  a  standard  cast  block.  A  piece  of 
60-lb.  rail,  3^  ft-  long,  was  bent  as  shown,  and  holes  were  cut  in  the 


*' 


FIG.    14. HOMEMAEE  BACKING-BLOCK. 

top  of  the  rail  for  the  accommodation  of  different  lengths  of  drill  steel. 
The  upper  end  of  the  rail  was  rested  on  the  anvil  block  and  pushed 
firmly  against  the  base  of  the  anvil.  To  hold  the  lower  end,  a  piece 
of  8  X  8-in.  timber  was  sunk  level  with  the  ground,  and  to  this  was 
firmly  spiked  a  10-  or  12-in.  piece  of  3^2  X  2J^-in.  iron;  one  end  was 
bent  up  as  shown,  and  had  a  slot  cut  in  it  just  to  fit  the  web  of  the 
rail. 

Coke  Furnace  for  Heating  Drills  (By  Claude  T.  Rice). — The  coke 
furnaces  used  at  the  Champion  mine,  at  Painesdale,  Mich.,  for  heating 
drills  for  sharpening  and  tempering  have  made  the  low  record  for  coke 
consumption  of  less  than  half  a  pound  of  coke  per  drill  sharpened  and 
tempered.  The  reason  for  this  low  consumption  is  that  the  coke,  as 
well  as  the  air,  is  preheated,  while  the  drills  are  heated  for  tempering  on 
the  same  fire  as  those  being  heated  for  the  machine  sharpener. 


16 


DETAILS  OF  PRACTICAL  MINING 


The  furnace,  as  shown  in  Fig.  15,  is  made  with  a  double  firebox, 
each  half  being  about  24  X  9  in.  inside  the  brick,  and  these  fireboxes  are 
separated  from  one  another  by  a  partition  made  of  firebrick  piled  length- 
wise across  the  wall.  The  firebox  is  10  in.  deep  and  fitted  with  a  shaking 
grate  designed  somewhat  on  the  principle  of  the  grates  in  the  firebox  of  a 
locomotive.  From  time  to  time  the  grates  are  shaken  and  the  clinkers 
broken  up  so  that  there  is  practically  no  burning  out  of  the  grate  bars. 


--WV 

FIG.    15. DRILL-HEATING  FURNACE  USED  AT  CHAMPION  MINE. 

The  wear  on  the  bricks  of  the  furnace  is  such  that  the  furnace  has  to  be 
relined  only  once  in  two  weeks,  12  firebricks  being  required  for  the  pur- 
pose. This  is  practically  the  only  maintenance  charge  there  is.  At 
each  end  a  hopper  projects  from  the  body  of  the  furnace.  These  hold 
the  coke  and  are  kept  filled  so  that  the  coke  is  thoroughly  heated  before 
going  down  on  the  fire.  This  coke  feeds  down  into  the  firebox  as  the  fire 
needs  it,  but,  from  time  to  time,  the  fire  has  to  be  poked,  and  the  coke 


SURFACE  PLANT  AND  OPERATIONS 


17 


spread  out.  This  is  done  through  the  coke  hopper,  a  hood  being  used  to 
take  out  of  the  shop  through  the  main  chimney  of  the  furnace  any  gases 
that  may  come  up  the  hopper.  This  hood  is  carried  by  a  sleeve  that 
goes  over  the  main  chimney  pipe  so  that  it  can  be  made  to  serve  the  other 
hopper  by  swinging  it  around,  holes  being  cut  in  the  main  pipe  to  permit 
this.  Generally,  only  one  end  of  the  furnace  is  used  at  a  time,  and  the 
heating  of  the  drills  for  sharpening  is  done  on  one  side,  while  on  the 
other  side  of  the  fire  the  drills  are  being  heated  for  tempering.  The 
path  of  the  air  through  the  furnace  is  shown.  It  comes  in  at  the  bottom 
and  is  taken  up  through  the  furnace  to  a  coil  of  pipe  on  top  of  the  furnace 
arch;  thus  the  hot  gases  have  to  play  around  the  coil  before  going  out  the 
chimney;  the  air  then  comes  down  to  the  bottom  of  the  furnace  again. 
In  this  way  any  water  in  the  air  is  converted  into  steam  and  the  air  is 
preheated.  This  causes  less  formation  of  clinkers  than  would  be  the 
case  if  wet  air  were  blown  under  the  grate. 

Joplin  Steel-sharpening  Kinks   (By  Claude  T.  Rice). — In  "the  lead 
and  zinc  districts  of  southwestern  Missouri,  "bull"  bits,  or,  as  they  are 

Chuck  dolt  Hut 


LJ 


u 


Horn  for 
Hardy  Hole. 


FIG.    16. — HANDLE  FOR  CHUCK  NUT 
ON   SWING  PISTON. 


FIG.    17. — BEVEL  SWAGE. 


more  generally  called,  chisel  bits,  are  employed  even  on  machine  steel. 
It  is  maintained  that  these  cause  less  trouble  in  "blocking  the  hole," 
the  local  term  for  fitchering.  Furthermore,  it  is  possible  for  one  man  to 
sharpen  the  chisel  bits,  while  two  are  usually  necessary  for  cross  bits. 
This  is  a  point  of  great  importance  in  a  small  property.  It  is  customary 
to  have  one  man  alone  do  the  sharpening  for  an  entire  mine  up  to  125 
drills  per  day. 

To  handle  the  larger  and  heavier  pieces  of  machine  steel,  however, 
special  devices  are  necessary.  Some  of  these  are  illustrated  in  Figs. 
16,  17,  18  and  19.  To  back  up  the  piece  of  steel-being  sharpened  an  old 
machine  drill  piston  is  used.  This  is  carried  in  a  horizontal  position  by  a 
suspension  hook  such  as  is  common  for  long  work  on  the  anvil.  The 
shank  end  of  the  drill  being  sharpened  is  inserted  in  the  old  piston 
chuck.  The  piston  has  one  nut  of  the  chuck  bolt  removed  and  the  other 
nut  fitted  with  a  device  for  setting  it  up  quickly,  Fig.  16. 

To  hold  the  bits  on  the  "stbving"  block  an  old  machine  drill  chuck 
is  frequently  set  in  the  block  under  the  anvil  so  that  the  drill  shank 


18 


DETAILS  OF  PRACTICAL  MINING 


enters  it  when  the  drill  is  laid  on  the  stoving  block.  This  latter  is  usually 
a  piece  of  80-lb.  rail  with  its  head  buried  in  the  ground,  the  steel  to  be 
stoved  resting  on  the  upturned  bottom  of  the  flange.  The  chuck  pre- 
vents swinging  of  the  steel  if  it  is  not  struck  quite  evenly  while  stoving. 
Two  anvils  are  generally  used,  the  second  one  being  under  the  air 
hammer  at  the  side  of  the  shop,  which  is  an  old  piston  drill  mounted  on  a 
pipe  sunk  in  the  ground.  The  process  of  sharpening  is  as  follows:  The 
hot  steel  is  first  placed  on  the  stoving  block  and  stoved  back  with  a  two- 
handed  sledge  weighing  from  8  to  10  Ib.  After  the  metal  has  been  stoved 


FIG.    18. SHOP   WITH    MOVABLE    HAMMER. 

back  to  forrn  the  bit,  which  has  a  face  angle  of  130°  to  140°  ordinarily, 
the  steel  is  transferred  to  the  anvil  under  the  machine  and  spread  out 
and  battered  down  to  gage.  The  end  of  the  piston  in  the  machine  has  a 
slightly  rounded  face.  The  long  pieces  are  supported  in  the  swing 
which  runs  on  a  piece  of  2-in.  pipe  across  the  top  of  the  shop.  From  this 
roughing  anvil,  the  steel  is  transferred  to  the  finishing  anvil.  If  it  is  a 
short  piece,  the  piston  is  found  useful  to  back  up  the  bit  with  its  weight 
and  relieve  the  smith  from  shock.  The  tightening  device,  shown  in 
detail,  is  made  of  a  piece  of  old  drill  steel  fitted  to  the  chuck-bolt  nut  and 
is  rather  heavy  so  that  by  slipping  the  drill  shank  in  the  chuck  of  tke 


SURFACE  PLANT  AND  OPERATIONS  19 

swinging  piston  and  giving  the  handle  a  spin,  the  bolt  is  sufficiently 
tightened.  The  weight  of  the  longer  drills  is  sufficient  to  take  the  shock 
of  the  dressing  blows.  In  dressing,  the  bit  is  usually  held  up  at  a  small 
angle  so  as  to  bevel  down  the  sides  slightly.  A  hook  somewhat  higher 
than  the  ordinary  hook  is  necessary  for  this,  but  the  same  result  can  be 
got  by  the  use  of  the  bevel  swage,  shown  in  Fig.  17,  which  has  a  horn  to 
fit  the  hardy  hole  of  the  anvil. 

The  layout  of  one  shop,  presented  in  Fig.  18,  is  somewhat  different. 
In  this  shop  all  the  work  is  done  on  one  anvil  and  the  stoving  block 
and  roughing  anvil  are  dispensed  with.  The  machine  is  mounted  on  an 
8  X  8-in.  timber,  which  runs  on  an  overhead  track  by  means  of  a  truck, 
as  shown,  and  can  thus  be  brought  into  service  on  the  one  anvil.  The 
air  hose  for  the  machine  is  kept  out  of  the  way  by  suspending  it  in  an 
eye-bolt  hung  from  the  crosspiece  of  the  truck. 

A  unique  method  of  tempering  the  steel  is  used.  It  is  a  modifica- 
tion of  the  plunging  method  that  retains  all  the  advantages  of  plunging 
while  there  seems  to  be  little  trouble  from  temper  checking  and  few 


Discharge  Plpe-^^ 


FIG.    19. TEMPERING  TROUGH  FOiJ  DRILL  BITS. 

drill  bits  break  off  at  the  shank.  The  method  consists  of  using  old  worn- 
out  jig  grates  to  form  a  shelf  to  support  the  drill  steel  in  the  tempering 
tank,  which  is  a  rectangular  box  about  12  in.  wide,  4  ft.  long  and  12  in. 
deep,  Fig.  19.  This  shelf  is  arranged  so  that  there  is  from  %  to  \Y± 
in.  of  water  on  top  of  the  grates.  In  a  few  instances  more  than  this 
depth  of  water  is  used  over  the  grates,  but  that  is  not  good  practice 
as  it  is  likely  to  result  in  breaking  off  of  the  steel  at  the  water  line.  The 
shelf  must  be  made  of  iron,  for  if  wood  were  used,  the  hot  drills  would 
burn  into  it  enough  so  that  the  bit  would  not  be  properly  cooled,  and  a 
soft  drill  would  result.  A  greater  depth  of  water  is  used  over  the  grates 
with  machine  sharpening  than  with  hand  work,  owing  to  the  fact  that 
it  is  more  difficult  to  keep  the  water  cool  with  the  faster  sharpening  done 
with  machines,  than  when  the  work  is  done  by  hand.  There  is  a  con- 
tinuous feed  of  water  going  to  the  tank,  and  the  amount  is  regulated 
so  that  when  a  drill  has  been  put  into  the  tank  the  temperature  of  the 
water  is  approximately  at  the  temperature  of  the  inflowing  water. 
By  this  method  the  tempering  can  be  done  in  one  heat  just  as  in  barrel 
plunging  and  there  is  no  necessity  of  bathing  the  steel  up  and  down  in 


20 


DETAILS  OF  PRACTICAL  MINING 


the  water  to  prevent  its  sudden  cooling  at  the  water  line  and  the  break- 
ing that  would  result.  The  reason  for  this  is  that  the  drill  bit  is  covered 
with  so  shallow  a  depth  of  water  that  the  steam  generated  by  the  hot 
steel  causes  the  water  line  to  play  up  and  down  on  the  metal  and  does 
the  bathing  automatically.  The  accompanying  drawing  shows  the 
trough  used  in  this  method  of  tempering  steel.  All  the  tool  sharpener 
does  is  to  hold  his  steel  for  the  right  temperature,  which  is  approximately 
that  at  which  he  finishes  the  sharpening  operation,  and  to  stand  the 
drill  on  the  grate  in  the  tempering  box.  Once  he  has  the  water  regulated 
properly,  he  has  to  pay  no  more  attention  to  it.  Both  bull  bits  and 
cross  bits  are  tempered  thus.  Some  blacksmiths  in  the  district  say  that 
they  have  been  able  to  get  as  good  results  by  this  method  as  by  draw 
tempering.  Draw  tempering  is  generally  used  on  the  hand  steel, 
although  some  hand  steel  is  also  tempered  by  this  plunging  method. 
The  machine  steel  chiefly  used  is  of  the  lower  carbon  grades  not  con- 
taining more  than  0.60  per  cent,  carbon. 


FIG.    20. SWAGE    FOR   SHARPENING    DRILLS   BY    HAND. 

Sharpening  Machine-steel  by  Hand  (By  Emory  M.  Marshall). — 
For  sharpening  machine-steel  at  a  mine  where  the  sharpening  is  done 
by  hand,  the  device  shown  in  Fig.  20,  designed  by  S.  J.  Collins  and  used 
by  the  McConnell  Mines  Co.,  is  of  value.  The  ordinary  dolly  used  for 
sharpening  is  drilled  at  the  four  corners  and  rods  of  %6~m-  iron  are 
screwed  into  each  hole.  The  dolly  is  then  mounted  in  an  anvil  block  or 
fastened  securely  to  the  floor.  The  rods  at  the  corners  may  be  of  any 
length,  say  12  to  18  in.  The  shortest  length  of  steel  that  can  be  sharp- 
ened depends  upon  the  length  of  these  rods,  so  they  must  be  short 
enough  to  accommodate  the  starters.  These  rods  are  fastened  at  the 
top  about  2  in.  apart  by  bolting  to  a  plate  of  J^-in.  iron,  which  has  been 
cut  out  at  the  center  to  allow  the  drill  to  pass  through  easily.  The 


SURFACE  PLANT  AND  OPERATIONS  21 

method  of  sharpening  is  the  same  as  the  old  method,  but  instead  of 
holding  a  dolly  on  the  bit  while  a  helper  strikes  it  with  a  heavy  hammer, 
the  blacksmith  drops  the  heated  steel  between  the  rods  and  pounds 
it  up  and  down  on  the  dolly.  The  iron  rods  are  set  so  close  to  the  corners 
that  the  steel  cannot  turn,  while  the  flare  at  the  top  allows  the  steel  to 
work  freely.  Of  course,  the  blacksmith  cannot  strike  as  heavy  blows 
as  his  helper  can  with  a  hammer,  but  by  working  the  drill  steel  up  and 
down  12  or  15  times,  he  can  get  as  good,  or  a  better,  bit  than  he  can 
by  having  a  helper  to  strike  for  him,  and  he  can  do  it  in  the  same  or 
less  time.  This  method  enables  one  man  to  sharpen  drill  steel  as  fast 
as  two  by  the  ordinary  method  of  hand  sharpening,  and  the  miners 
claim  that  the  bits  are  better. 

Tempering  Hand-drill  Steel  (By  Albert  G.  Wolf).— A  simple  but 
satisfactory  method  of  tempering  hand-drill  steel  was  originated  by 
John  Sommers,  foreman  of  the  Blue  Jay  mine  of  the  Mason  Valley  Mines 
Co.,  and  is  in  use  at  that  mine.  It  consists  of  heating  the  drill  to  a  dull 
red  for  a  distance  of  about  1  in.  back  from  the  edge  of  the  bit,  then 


FIG.    21. CONVENIENT  METHOD  OF  HAND-STEEL  TEMPERING. 

placing  one  side  of  the  bit  just  flush  with  the  surface  of  the  water,  as 
shown  in  Fig.  21.  The  water  will  climb  up  on  the  bit  at  X  as  long  as 
sufficient  heat  remains  in  the  steel.  When  the  water  ceases  to  climb, 
the  steel  is  removed  and  allowed  to  cool  slowly.  At  the  time  of  removal 
the  temper  is  extremely  hard,  but  the  heat  remaining  in  the  steel  will 
draw  back  into  the  bit  and  toughen  it.  Drills  sharpened  in  this 
manner  never  check,  as  the  first  cooling  is  almost  uniform  throughout; 
corners  of  the  bit  are  rarely  broken  off;  and  the  edge  of  the  bit  is  resist- 
ant to  the  wear  against  hard  rock.  The  temper  can  be  regulated  closely 
by  the  degree  of  water  cooling. 

U-Bolt  Bending  Tool  (By  Dan  Fields). — In  Fig.  22  is  shown  a  device 
for  bending  piston-machine  U-bolts  without  battering  the  threads.  It 
is  adapted  for  making  bolts  for  a  3^-in.  drill,  although  it  can  be  used 
for  smaller  bolts  if  they  are  given  one  blow  on  the  anvil.  To  use  the 
machine,  the  bolt  is  heated,  placed  on  the  center,  clamped  with  the 
handle  and  bent  down  with  a  wood  or  rawhide  mallet.  The  square- 
section  projection  on  the  bottom  should  be  of  the  proper  size  to  fit  the 


22 


DETAILS  OF  PRACTICAL  MINING 


anvil   hardyhole.     The  handle  is  about  3  ft.  long  and  made  of  1-in. 
round  mild  steel.     It  gives  sufficient  leverage  to  hold  the  bolt  firmly. 

Compressed-air  Jet  for  Cleaning. — Where  many  machine  drills  are 
being  operated,  much  time  may  be  saved  to  the  repair  man  by  using  an 
air  jet  for  cleaning  various  drill  parts,  such  as  cylinders,  barrels,  front 
heads  and  valve  chests.  A  H-in.  pipe  line  is  connected  to  the  receiver 
or  air  main,  wherever  it  is  most  convenient,  and  a  line  is  run  to  the  work 
bench.  A  globe  valve  is  placed  in  the  line,  and  beyond  the  valve,  two  J^-in. 
lines  are  taken  off.  One  consists  of  a  nipple,  followed  by  a  globe  valve  and 


Bolt 


FIG.    22. IfcEVICE  FOR  SHAPING  MACHINE-DRILL  U-BOLTS. 

a  t-ft.  length  of  ^-in.  pipe.  The  end  of  this  piece  is  drawn  out  to  form  a 
nozzle.  The  other  consists  of  a  globe  valve  followed  by  a  length  of  J^-in. 
rubber  hose  and  a  J^-in.  nozzle.  The  first  jet  is  convenient  for  cleaning 
small  parts  which  are  easily  handled;  the  second  for  larger  parts,  or  parts 
which  may  be  clamped  in  the  vise. 

Devices  for  Bending  Plates  (By  Claude  T.  Rice). — It  often  becomes 
necessary  to  bend  iron  plates  in  a  mine  shop,  particularly  where  the  mine 
manufactures  its  own  cars.  In  the  shops  of  the  Desloge  Consolidated 
Lead  Co.  of  southeastern  Missouri,  two  devices  are  in  use  for  this  purpose. 

In  Fig.  23  (elevation)  is  shown  a  vise,  made  of  two  60- Ib.  rails  set 


SURFACE  PLANT  AND  OPERATIONS 


23 


horizontally,  one  below  the  other,  with  the  flanges  facing  each  other. 
The  plate  is  inserted  between  these  rails,  which  are  screwed  together 
and  the  bending  done  by  hammering.  The  lower  rail  is  set  on  two  posts 
in  notches,  and  projects  a  few  inches  beyond  each  post.  The  web  and 
head  are  cut  away  at  the  ends  and  the  flange  drilled  to  permit  the  passage 
of  the  vise  screws.  These  screws,  made  from  the  feed  screws  of  machine 
drills,  work  in  nuts,  which  are  under  the  flange,  and  have  lugs  bearing 

Feed  Sere*  from  Spanner  Handle 

3'' Machine  Drill  n*' 

X     .-  60  Ik  Rail,  (lovable 


I?  Eye  bolt 

FIG.    23. CLAMP  AND  BENDING  DEVICE  FOR  STEEL  PLATES. 

against  the  posts  to  prevent  turning.  Collars  are  riveted  to  the  web  of 
the  upper  or  movable  rail  which  is  shorter  than  the  lower  rail  and  these 
collars  project  sufficiently  to  allow  the  screws  to  work  through  them. 
In  the  drawing  the  upper  rail  is  shown  lifted  to  admit  a  plate.  The  tops 
of  the  screws  are  fitted  with  double-ended  spanners  to  serve  as  handles 
for  tightening  and  loosening.  The  vise  is  capable  of  handling  plates  up 
to  %  in.  in  thickness. 


24  DETAILS  OF  PRACTICAL  MINING 

§ 

An  apparatus  which  includes  a  bending  device  and  eliminates  ham- 
mering is  shown  in  Section  A-A  and  in  plan,  Fig.  23.  It  consists  of  two 
timbers  side  by  side,  by  which  the  plate  is  clamped  vertically,  and  another 
timber  moving  on  bolts,  which  does  the  actual  bending.  The  clamping 
timbers  are  12  X  12  in.,  their  upper  adjacent  edges  being  bound  with 
4  X  4  X  J^-in.  angles.  Two  1^-in.  horizontal  bolts  with  suitable  washer 
plates  and  nuts  on  one  end,  are  used  for  clamping.  The  opening  between 
the  timbers  is  adjusted  by  these  to  any  width,  so  as  to  control  the  sharp- 
ness and  the  amount  of  the  bend.  Through  the  fixed  12  X  12-in.  timber 
are  two  vertical  IJ^-in.  eye-bolts  and  linked  into  these  so  as  to  form  a 
hinge  are  two  horizontal  lj^-in.  eye-bolts.  These  latter  pass  through 
the  6  X  6-in.  bending  timber,  and  by  means  of  nuts  on  their  ends,  this 
timber  is  drawn  horizontally  against  the  vertical  clamped  plate  and  bends 
it  down.  On  the  top  bearing  edge  of  this  timber  are  two  clips  or  buttons 
which  can  be  turned  out  to  come  over  the  top  of  the  plate  and  by  swinging 
the  timber  up  somewhat,  the  bending  of  the  plate  can  be  started  above 
the  clamping  line. 

Homemade  Timber-framing  Plant  (By  Frank  M.  Leland). — In 
order  to  avoid  purchasing  an  expensive  timber-framing  machine,  the 
Empire  Copper  Co.,  of  Mackay,  Idaho,  devised  a  rig  out  of  scrap  machinery 
from  about  the  mine,  together  with  a  new  slabber  including  saw,  and  a 
swinging  cut-off  saw.  Fig.  24  shows  the  general  features  of  construction. 
A  frame  was  built  of  8  X  8-in.  timbers  and  the  cut-off  saw  frame  laid 
horizontally  upon  it  instead  of  vertically.  An  old  vertical  7  X  10-in. 
engine  was  connected  as  shown,  using  channel  irons  with  slotted  holes 
so  that  the  saw  frame  could  move  up  and  down,  cutting  any  depth  desired, 
or  could  be  lowered  clear  down  and  used  to  square  the  timbers.  Another 
saw  running  horizontally  was  rigged  up.  This  does  not  cut  at  the  same 
time  as  the  vertical  saw;  hence,  only  power  enough  is  required  to  drive 
one  saw  at  a  time.  The  guide  rails  under  the  table  were  made  from  1  J£- 
in.  square  iron  set  edgeways;  the  rollers  were  turned  out  of  some  matte 
pans;  the  pulleys  and  shafting  were  picked  up  around  the  place.  The 
machine  is  strictly  homemade,  but  it  is  good  and  strong  and  it  runs 
perfectly. 

The  posts  are  first  sawed  on  the  slabber;  they  are  next  squared  on  the 
ends  by  running  through  the  machine,  say  one  hundred  of  them;  the  saw 
is  then  raised  up  so  as  to  cut  just  2  in.  deep.  The  .horizontal  saw  remains 
stationary;  the  stick  is  shoved  through  and  the  cut  made  on  top;  the 
carriage  is  then  shoved  on  the  horizontal  saw  and  a  slice  taken  out  of  the 
bottom;  it  is  then  pulled  back  and  rolled  over  one-quarter  and  the  opera- 
tion repeated;  it  requires  four  cuts  to  finish  the  end.  It  averages  3J^ 
rain,  to  frame  both  ends  of  an  8  X  8-in.  post. 

The  slabber  takes  logs  up  to  8  ft.  in  length.     A  set  of  dogs  was  made 


SURFACE  PLANT  AND  OPERATIONS 


25 


and  some  perforated  plates  to  hold  pins,  and  an  inserted  tooth  saw  used  to 
replace  the  thin  saw  which  came  with  the  slabber.  The  machine  will 
not  only  make  square-set  timbers  but,  using  logs  8  ft.  long,  it  will  make 
lumber  for  just  about  one-half  its  cost  when  purchased  from  the  saw 
mills.  It  will  also  saw  2  X  4-in.  stuff  for  ladders,  4  X  6-in.  for  flooring 
for  the  square  sets  and  almost  anything  up  to  8  ft.  long.  The  2  X  12- 
in.  by  8-ft.  lumber  is  found  just  as  good  for  chutes,  etc.,  as  is  16-ft. 
The  ends  are  squared  before  sending  to  the  mine,  making  the  planks 
exactly  8  ft.  long  and  by  putting  the  sets  in  the  chutes  on  4-ft.  centers, 
there  is  no  sawing  to  be  done  in  the  mine  by  candle  light  with  a  dull  saw ; 
this  saves  money.  A  little  wedge  saw  was  rigged  to  use  up  the  scraps, 
and  wedges  cost  %  ct.,  as  against  6  cts.,  made  by  hand.  Ladder  rounds 
2J--2  m-  square  by  16  in.  long  are  made  by  ripping  them  on  the  small 
mill.  The  great  advantage  from  the  whole  plant  is  that  from  every 
timber  are  got  four  slabs,  two  of  which  are  generally  good  for  lagging  and 


-  FIG.  24. FRAMER,  SHOWING  BED,  CARRIAGE  AND  SAWS. 

in  almost  every  case  enough  lagging  is  had  from  the  timber  to  pay  for  the 
timber  itself,  since  2-in.  plank  would  be  used  otherwise.  Furthermore, 
the  boiler,  being  purposely  left  naked,  warms  up  one  end  of  the  shop  and 
for  the  other  live  steam  in  coils  of  pipe  is  used ;  the  fuel  costs  nothing  since 
sawdust  is  burned.  This  is  quite  an  item,  as  it  ordinarily  takes  from  300 
to  400  Ib.  of  coal  daily  to  keep  the  shop  warm. 


HANDLING  SUPPLIES 

Pipe  Rack. — A  satisfactory  and  convenient  pipe  rack  for  the  mine 
warehouse  is  illustrated  in  Fig.  25.  The  larger  pipes  are  stored  on  the 
base  and  lower  arms,  and  lighter  pieces  on  the  upper  arms.  Iron  bars 
and  structural  shapes  may  also,  of  course,  be  handled  in  the  rack.  The 
rack  possesses  the  great  convenience  of  permitting  the  pieces  to  be 
extracted  either  lengthwise  or  sideways,  and  by  setting  it  in  the  middle 
of  the  room,  both  sides  are  made  accessible. 


26 


DETAILS  OF  PRACTICAL  MINING 


It  consists  of  a  number  of  bents  spaced  4  ft.  apart.  Six  bents  would 
thus  give  a  length  of  20  ft.,  sufficient  to  accommodate  standard  pipe. 
Five  bents  would  probably  be  just  as  satisfactory.  Each  bent  consists 
of  a  center  post  8X8  in.,  with  inclined  pieces  6  X  6  in.  symmetrically 
placed  on  each  side.  The  base  is  an  8  X  8-in.  by  10-ft.  piece  and  suit- 
able bracing  is  provided  at  the  bottom.  The  line  of  bents  is  tied  by  a 


— -  5'    >j<"™~ 

FIG.    25. END  VIEW  OF  PIPE  RACK. 


horizontal  8  X  8-in.  piece  along  the  top  of  the  center  posts,  a  6  X  6-in. 
piece  at  its  bottom  and  an  8  X  8-in.  chamfered  piece  along  the  ends 
of  the  bases.  The  upper  diagonal  arms  should  be  supported  by  iron 
braces  similarly  to  the  lower  set,  although  these  are  not  shown  in  the 
illustration.  These  6  X.6-in.  diagonal  arms  should  also  be  mortised 
into  the  center  post  with  either  inclined  or  square  mortises,  as  shown 
on  the  lower  two  sets. 


SURFACE  PLANT  AND  OPERATIONS 


27 


Carbide  Container  and  Measurer  (By  E.  W.  R.  Butcher). — With 
the  introduction  of  carbide  lamps,  it  has  been  found  unsatisfactory  to 
allow  the  miners  to  help  themselves  from  the  carbide  cans.  The 
Republic  Iron  &  Steel  Co.  therefore  furnishes  each  of  its  miners  with  a 
small  screw-top  can  which  holds  enough  carbide  to  last  one  shift.  These 
cans  are  filled  from  the  carbide  container,  a  drawing  of  which  is  shown 


|r  Sq.  rina  -threaded 
\  ford  standard  pipe  and/, 

riveted  to  top  plate  of 
\   \\    container 

U4°\ .,o<- r-i.A 


FIG.    26. ASSEMBLED  CARBIDE  CONTAINER  AND  DETAILS  OF  CERTAIN  PARTS. 

in  Eig.  26.  By  means  of  the  valves,  one  motion  of  the  lever  arm,  up  or 
down,  gives  out  just  enough  carbide  to  fill  a  miner's  can."  The  spill 
pan  is  used  to  catch  any  carbide  which  falls.  Since  the  container  has 
been  in  use,  the  carbide  consumption  has  been  reduced  nearly  one-half. 
A  screw  top  with  a  H-in.  pipe  for  a  lever  handle  is  provided  on  the 
top  of  the  container.  The  carbide  issues  from  the  container  bottom 
through  a  2-in.  pipe  connection.  In  this  connection  are  set  two  valves, 


28 


DETAILS  OF  PRACTICAL  MINING 


each  consisting  of  a  seat  and  a  plate,  in  both  of  which  are 
holes.  The  plate  slides  over  the  seat,  and  when  the  holes  register, 
the  valve  is  open  and  carbide  can  pass.  When  the  holes  do  not 
overlap  at  all,  the  valve  is  closed.  The  sliding  back  and  forth  of 
the  valve  plates  is  effected  by  the  lever  arranged  to  close  one  valve 
while  opening  the  other.  Between  the  valves  is  a  3^-in.  nipple  of  2-in. 
pipe,  which  forms  the  measuring  box.  A  chain  connection  between  the 
pipe  handle  of  the  cap  and  the  end  of  the  operating  lever  can  be  kept 
locked.  The  details  of  the  construction  of  the  entire  apparatus  can 
be  seen  in  the  drawing. 


STEAM-SHOVEL  WORK 

Changing  Dipper  Teeth  on  Steam  Shovels  (By  Clarence  M.  Haight). 
— When  digging  iron  ore  with  a  steam  shovel,  it  becomes  necessary, 
at  intervals  of  two  or  three  weeks,  to  replace  the  dull  dipper  teeth  with 
sharp  ones.  As  there  are  four  teeth  used  on  a  dipper,  the  time  thus 


In  side  Face 
.of  Dii 


TOOth  : 


FIG.    27.  —  HOLDING   STRAP. 


5  trap 


'•  Face  of  Dipper 
FIG.    29. TOOTH  INSERTED. 


Wedge 


\ 

i 

1 
1 

H- 

~-—  . 

Pace  of 
Dipper- 


Slrap    I 
FIG.    28. TOOTH   IN    STRAP 


spent  in  the  course  of  a  season  is  an  important  item.  Formerly  a 
tooth  was  fastened  to  the  dipper  with  six  1-in.  bolts.  With  this  method 
much  trouble  was  experienced;  for,  unless  there  was  absolutely  no  play 
between  the  dipper  and  the  tooth,  the  whole  strain  of  the  digging  came 
on  the  bolts,  which  bent  so  much  that  it  was  difficult  to  remove  them. 
On  this  account  the  changing  of  a  tooth  was  generally  done  on  Sunday 
in  order  not  to  delay  operations.  As  it  is  not  necessary  to  change  all 
the  teeth  at  the  same  time,  a  part  of  almost  every  Sunday  had  to  be 
devoted  to  this  work. 

At  many  mines  now  a  new  method  of  attachment  is  in  use,  which 
makes  the  removal  and  the  replacement  of  a  tooth  a  comparatively 
simple  matter.  A  strap  of  %  X  5-in.  iron,  bent  as  shown  in  Fig.  27, 
is  riveted  inside  the  dipper  on  the  face  which  digs  the  ore.  The  dipper 
tooth  has  a  lug  projecting  from  one  side  near  the  back  end,  as  shown 
in  Fig.  28.  The  loops  in  the  strap  are  wide  enough  to  admit  the  tooth 
and  this  lug  easily.  When  the  lug  is  behind  the  strap  the  inset  part  of 
the  tooth  fits  against  the  edge  of  the  dipper.  The  end  of  the  tooth  is 


SURFACE  PLANT  AND  OPERATIONS  29 

pushed  to  one  side  until  it  touches  the  side  of  the  strap.  A  wooden 
wedge  is  then  driven  in  between  the  tooth  and  the  other  side  of  the  strap 
to  hold  the  lug  in  place,  completing  the  operation.  The  lug  prevents 
the  tooth  from  falling  out  and  the  edge  of  the  dipper  takes  all  the  strain, 
as  it  should.  The  inserted  tooth  is  shown  in  Fig.  29.  To  remove  the 
tooth  the  operation  is  reversed;  the  wedge  is  driven  out,  any  dirt  in  the 
way  is  removed,  the  tooth  is  shoved  to  one  side  until  the  lug  will  clear 
the  strap,  and  the  tooth  is  then  pulled  off. 

Grade  Board  (By  L.  B.  Pringle). — A  grade  board  used  extensively 
in  steam-shovel  mining  around  Hibbing,  Minn,  is  shown  in  Fig.  30. 
The  novel  feature  of  the  device  consists  in  the  fact  that  the  measure- 
ments are  so  adjusted  that  the  terms  "per  cent."  and  "inches"  are 
interchangeable. 

The  necessary  equipment  consists  of  a  board,  1  X  8  in.  by  10  ft., 
having  its  two  edges  carefully  planed  and  parallel,  of  one  small  car- 
penter's spirit  level,  of  two  round  iron  pins  %  X  24  in.,  having  standard 
flat  bolt  heads,  and  of  a  supply  of  wood  suitable  to  cut  into  small  blocks 

Direci-fonof  Travel 


:^?  — 1 — -_,; ~I  I/  __/ 

Pine  Board  fx8"x/o\ 


ZL__ET ™  !^^^^™TT"~"^ 

_.        ,  //O^^^^^W^Ty^/ASV/AXy^^ 

r//7  %)(£4-- — -T  /    //  fr 

r  -i 

FIG.    30. GRADE  BOARD  -IN  USE. 


of  various  thicknesses.  A  handle  1  X  1%  X  5  in.  may  be  cut  in  the 
board  to  facilitate  carrying.  The  pins  are  spaced  exactly  8  ft.  4  in. 
apart,  parallel  to  the  direction  of  travel  of  the  shovel,  and  are  driven 
close  to  the  ground.  By  means  of  the  board  and  level  the  pins  are 
brought  to  the  same  elevation.  Then  for  down-grades  a  grade  block 
is  placed  under  the  board  on  top  of  the  rear  pin;  for  up-grades,  under 
the  board  on  top  of  the  front  pin.  For  a  1.0  per  cent,  grade  there  is 
used  a  1-in.  block;  for  a  1.5  per  cent,  grade  a  IJ^-in.  block;  etc.  The 
illustration  shows  the  application  of  the  method  in  running  a  2.25 
per  cent,  down-grade.  The  shovel  runner  sights  along  the  upper  edge 
of  the  board  at  a  graduated  stick  or  rule  held  upright  by  a  helper  at 
various  points  along  the  line,  and  knowing  the  depth  below  grade  he  is 
to  carry  throughout  the  course,  and  the  height  of  the  top  of  the  board 
above  the  ground,  he  can  readily  ascertain  the  depth  of  cut  needed  at 
any  point.  The  percentage  of  error  increases  with  the  length  of  sight 
taken  from  a  set-up;  but  by  making  two  and  sometimes  three  set-ups 
a  day  the  error  found  by  checking  with  the  engineers'  leveling  is  so 
small  that  it  can  be  disregarded. 


30 


DETAILS  OF  PRACTICAL  MINING 


Track  Connections. — Much  time  is  lost  in  steam-shovel  work  in 
"moving  up."  This  loss  is  usually  due  either  to  derailment  on  account 
of  poor  track  laying  or  to  the  slowness  with  which  the  crew  makes  the 
connections.  In  order  to  save  time  the  arrangement  for  connecting  track 
sections,  illustrated  in  Fig.  31,  has  been  devised  and  used  in  many  pits 
on  the  Mesabi  iron  range.  Not  only  does  it  save  time  in  laying  the  track, 
but  insures  a  connection  that  the  wheels  will  pass  over  without  danger 
of  derailment.  It  consists  of  two  4  X  6-in.  angles,  shop  riveted  to  a  M-in. 
plate,  which  is  as  wide  as  the  tie  used  and  long  enough  to  accommodate 
the  size  rail  used  in  the  sections.  The  angles  are  spaced  Y±  in.  wider 
than  the  width  of  the  base  of  the  rail.  The  holes  for  connecting  the  rails 
are  spaced  and  bored  as  in  ordinary  angle  bars,  except  that  there  is  but 


L,4 


Shop 
:  Riveted 


C 


ofc 


FIG.    31. ANGLE-BAR,    STEAM-SHOVEL   TRACK    CONNECTIONS. 

one  hole  for  each  rail,  which  is  M  m  larger  in  diameter  than  the  bolts  in 
order  to  lessen  the  difficulty  in  making  the  joint.  Two  plates,  with  their 
upright  angles,  are  bolted  to  a  good  tie,  as  shown  in  the  accompanying 
drawing.  It  is  customary  to  bolt  the  connecting  tie  to  the  front  section 
while  the  steam  shovel  is  at  work.  As  soon  as  the  whistle  blows  to 
move  up,  the  rear  section  is  carried  forward;  and  it  is  only  necessary  to 
pass  a  bolt  through  each  plate  to  make  the  connection  instead  of  having 
trouble  with  two  pairs  of  angle  bars. 

Rigid  Track-connection  (By  E.  C.  Kingston). — The  rail  chair  or 
track  connection  illustrated  in  Fig.  32  has  the  advantage  over  that  just 
described  of  affording  greater  rigidity,  as  it  fits  over  the  base  of  the  rail 
and  prevents  a  sideways  roll.  The  chair,  made  by  the  Bucyrus  Co.,  is 
a  steel  casting  fitting  the  rail  loosely,  its  length  corresponding  to  the  width 


SURFACE  PLANT  AND  OPERATIONS 


31 


of  a  tie,  8  in.  In  steam-shovel  work,  the  new  track  usually  lies  on  an 
up-grade,  since  the  shovel  tends  to  imbed  the  section  on  which  it  rests. 
This  fact,  combined  with  the  rough  bottom  and  the  necessity  of  providing 
for  side  swing,  accounts  for  the  large  clearance  allowed,  the  short  length 
of  the  casting  and  the  placing  of  the  holes  for  the  pins  near  the  ends  of 
the  rolls.  The  pins  are  not  threaded  and  can  be  quickly  inserted  and 
removed.  They  are  chained  to  the  casting  to  prevent  losing.  Both  of 
the  rail  ends  lie  on  one  metal  plate  and  the  tops  are  thus  always  main- 
tained at  the  same  level,  which  is  not  always  possible  when  using  bridle- 
bars.  More  clearance  is  allowed  on  the  sides  of  the  rail  base  than  shows 
in  the  illustration,  in  order  to  permit  swinging  the  rail  in  making  a  curve. 


o 


o 


FIG.   32. — CAST-STEEL  TRACK  CONNECTIONS. 

Backing  Block  (By  L.  B.  Pringle). — The  block-and-clamp  device 
of  Fig.  33,  was  developed  and  adopted  for  its  steam  shovels  by  the  Oliver 
Iron  Mining  Co.,  Hibbing,  Minn.  It  is  of  simple  construction,  is  quickly 
and  cheaply  made,  is  easy  to  handle,  and  has  proved  a  success.  The  block 
is  placed  against  the  hind  wheel  of  a  steam  shovel  and  prevents  any  back- 
ward movement  of  the  machine  as  the  dipper  gouges  into  the  dirt,  or 
when  the  shovel  is  working  on  an  up-grade. 

The  material  for  block,  clamp  and  pin  is  wrought  iron.  The  block  is 
made  from  1  X  2%-m.  stock  bent  into  a  right-angled  triangle  with  dimen- 
sions as  shown.  The  clamp  is  of  1  X  2^-in.  stock,  made  to  fit  snug  over 
the  rail  and  through  the  block.  The  holes  in  the  sides  of  the  clamp  are 
cut  to  fit  a  pin  1  X  1%  in.  tapered  to  1  X  1  in.  and  10  in.  long.  The 
distance  from  the  top  of  the  clamp  to  the  upper  edge  of  the  holes  is  7% 
in.,  thus  allowing  J^-iri.  play  beneath  the  bottom  of  the  rail.  There  is 
approximately  10  in.  of  longitudinal  play  between  the  clamp  and  the 
inner  edges  of  the  block.  This  permits  the  clamp  to  be  placed  against  a 


32 


DETAILS  OF  PRACTICAL  MINING 


tie,  and  the  block  so  adjusted  as  to  have  its  working  face  over  the  tie  or 
beyond  it.  If  the  block  is  inclined  to  slip,  a  small  iron  or  wooden  wedge 
inserted  between  the  block  and  rail  at  the  rear  end  will  make  it  secure. 
Unless  the  shovel  is  unusually  large  or  is  working  in  extremely  hard 


Wedge 
be  used 
here- 


Taper  Pi n 


FIG.    33. — ASSEMBLED  PARTS  OF  STEAM-SHOVEL  BLOCK. 

ground  or  is  on  a  maximum  up-grade,  one  block  and  clamp  will  be 
sufficient. 

MISCELLANEOUS  NOTES 

Cooler  for  Drinking  Water  (By  E.  W.  Durfee). — For  those  living  in 
arid  regions,  where  a  supply  of  ice  is  not  always  available,  the  apparatus 


y  "Holes  spaced  2  " 


'-To  Wafer  3uppJy  "  ---2L0--  -  -+\ 

FIG.    34. SMALL-SIZE  RADIATOR-TYPE  WATER  COOLER. 

herein  described  will  be  found  satisfactory  for  supplying  cool  drinking 
water.  One  has  been  in  use  at  the  Alvarado  mine  for  at  least  two  sum- 
mers and  has  been  found  superior  in  every  way  to  the  olla,  so  commonly 
used  throughout  the  southwestern  United  States.  It  is  more  efficient  as  a 


SURFACE  PLANT  AND  OPERATIONS  33 

cooler,  is  perfectly  sanitary  and  does  not  require  the  attention  for  filling 
and  cleansing  that  is  necessary  with  the  other  device.  Its  efficiency,  of 
course,  depends  upon  the  amount  of  humidity  in  the  atmosphere,  but 
for  average  conditions  in  Arizona  the  difference  between  the  temperatures 
of  the  wet  and  dry  thermometers  in  summer  is  about  30°,  and  sometimes 
runs  as  high  as  40°.  Fig.  34  shows  the  construction,  the  whole  being  made 
up  of  J^-in.  pipe  and  fittings.  The  pipes  and  return  bends  should  be 
wrapped  with  thin  cloth  and  placed  in  a  shaded  open  place,  where  the 
prevailing  winds  will  cause  the  maximum  evaporation.  The  drip  from 
the  upper  pipe  should  be  regulated  by  means  of  the  valve  B  to  just  the 
amount  necessary  to  keep  wet  the  pipes  below.  As  the  cool  water  is 
drawn  from  valve  A  it  can  readily  be  seen  from  the  drawing  that  the  pipes 
are  kept  filled  from  the  water  supply.  With  an  apparatus  of  the  size 
shown,  about  10  glasses  of  cool  water  can  be  drawn  at  one  time,  after 
which  it  will  take  about  15  min.  to  cool  another  supply  to  the  minimum 
temperature  it  will  attain. 

[An  excellent  portable  alternative  device  is  a  coarse-canvas  bag  with  a  bottle  neck 
sewed  into  one  corner,  the  "South  African  Water  Bag." — EDITOR.] 

Elevating  Guy  Lines  (By  L.  E.  Ives). — The  height  at  which  guy  lines 
generally  cross  paths  is  just  about  that  necessary  to  strike  one  in  the  neck. 
It  is  possible  to  overcome  this  difficulty  at  slight  expense  and  at  the  same 
time  provide  a  perfectly  strong  anchor.  A  concrete  post,  reinforced 
with  two  30-lb.  rails,  is  made  with  a  total  length  of  10  ft.  The  upper 
6-ft.  section  of  this  post  is  circular  in  cross-section  and  12  in.  in  diameter. 
The  remainder  is  square,  20  in.  on  a  side.  The  square  section  is  placed 
in  the  ground,  and  the  round  portion  extends  above  ground.  An  eye^ 
bolt  is  embedded  in  the  top,  and  the  guy  line  is  attached  to  this.  In 
this  way  the  line  at  its  lowest  point  is  6  ft.  above  the  ground,  giving 
clearance  usually  sufficient. 

Arc -light  Tower. — The  details  of  construction  of  an  arc-light  tower, 
made  chiefly  of  pipe,  and  used  at  the  mines  of  the  St.  Louis  Smelting 
&  Refining  Co.  in  southeastern  Missouri,  are  shown  in  Fig.  35.  These 
towers  are  used  to  support  the  lights  that  illuminate  the  yards  in  the 
immediate  vicinity  of  the  main  shafts  and  shops. 

The  legs  A  of  the  towers  are  pieces  of  1^-in.  pipe  set  in  concrete 
pedestals  at  a  batter  of  %  in.  per  foot.  The  three  pipes  are  tied  to- 
gether at  intervals  of  4  ft.  by  means  of  the  crossbraces  B,  made  of 
%  X  1^-in.  steel  cut  to  the  proper  length,  together  with  the  standard 
clamps  J,  made  of  the  same  size  of  steel,  bent  to  the  shape  shown  and  held 
together  by  bolts,  20°  malleable-iron  angle  washers  E  being  used  on  the 
coupling  bolt  F.  At  the  top  there  are  two  triangular  plates  C  and  D, 
that  slip  over  the  legs.  These  are  made  so  as  to  ride  the  legs  about  18 


34 


DETAILS  OF  PRACTICAL  MINING 


in.  apart.  The  caps  /  are  screwed  on  the  top  of  the  legs  after  the  plate 
has  been  put  on.  In  the  center  of  these  plates  a  hole  is  bored  to  re- 
ceive the  pipe  G,  also  made  of  two  pieces  of  IJ^-in.  pipe  put  together 
with  an  elbow  and  reinforced  by  an  angle  brace  of  %  X  IJ^-in.  steel. 


TCFTTr 

wh 


Detail  of  Clamp 
FIG.    35. ARC-LIGHT  TOWER  FOR  SURFACE  USE. 

On  this  top  piece,  which  carries  the  arc  light,  are  two  collars  H,  that  rest 
upon  the  two  triangular  plates.  Owing  to  the  way  that  the  three  legs 
are  strapped  together,  all  the  fittings  are  standard  and  the  cost  of  the 
towers  is  small. 


II 

EXPLOSIVES 

Blasting    and    Handling    Explosives — Storage    and    Thawing — Safety 

Precautions 

BLASTING  AND  HANDLING  EXPLOSIVES 

Mammoth  Blasting  by  Electricity  (By  E.  Hibbert). — At  the  Mother 
Lode  mine  of  the  British  Columbia  Copper  Co.  in  British  Columbia,  the 
ore  is  broken  off  in  large  slices  at  infrequent  intervals,  several  hundred 
thousand  tons  being  broken  in  one  blast.  Electrical  blasting  is  used 
for  this  work.  In  the  big  blast,  of  October,  1911,  the  method  used 
was  similar  to  subsequent  blasts,  and  may  be  described  as  typical. 

Loading  started  on  the  morning  of  Oct.  2,  at  7  a.m.,  and  continued 
until  the  morning  of  Oct.  4,  at  1  a.m.  All  the  machinemen  were  em- 
ployed loading  the  holes  under  the  supervision  of  the  foreman  and  shift 
bosses.  The  detonators  were  given  to  specially  selected  men,  whose 
sole  duty  during  the  loading  was  to  make  up  the  primers  and  hand  them 
to  the  loaders,  seeing  that  the  wires  of  the  detonators  were  carefully 
unwound  and  free  from  kinks.  The  electrician  commenced  stringing 
lead  wires  on  the  morning  of  Oct.  3,  and  when  this  was  finished  he 
started  wiring  up  the  most  distant  sections,  connecting  all  holes  in 
series  of  25  to  the  lead  wires.  At  1  a.m.,  Oct.  4,  a  special  wiring  crew, 
consisting  of  the  superintendent,  foreman,  shift  bosses  and  a  few  picked 
men  was  put  on  under  the  charge  of  the  electrician  and  the  wiring  com- 
pleted. The  blast  was  exploded  at  10:30  a.m.  and  broke  175,000  tons 
of  ore. 

In  this  blast  2433  holes  were  loaded  with  10^  tons  of  40  per  cent, 
dynamite.  The  holes  were  connected  to  the  lead  wires  in  series  of  25, 
using  2525  Nobel's  No.  7  low-tension  detonators  with  8-ft.  lead  wires, 
the  extra  detonators  being  used  to  make  up  the  series  of  25  detonators 
in  a  circuit  in  places  where  the  holes  could  not  easily  be  connected  up  to 
the  lead  wires  in  series  of  25.  When  everything  was  ready  for  the  blast, 
the  main  lead  wires  were  connected  to  a  550-volt,  alternating-current 
circuit.  The  main  lead  wires  from  the  transformers  were  of  No.  1, 
rubber-covered  copper  wire,  and  from  these  No.  6  and  No.  8  weather- 
proofed  copper  wires  led  off.  No.  10  and  No.  12  weather-proofed 
copper  wires  again  led  from  the  No.  6  and  No.  8  wires  for  the  shorter 
circuits.  All  joints  on  the  leads  were  covered  with  friction  tape. 

35 


36  DETAILS  OF  PRACTICAL  MINING 

The  No.  7  low-tension  detonators  with  8-ft.  lead  wires  have  a  re- 
sistance of  one  ohm  and  require  J^  amp.  for  detonation.  In  the  blast 
described,  there  were  101  circuits  with  25  holes  in  series  in  each  circuit, 
and  as  a  current  of  %  amp.  was  required  in  each  circuit,  a  current  of 
101  X  0.5,  or  50.5  amp.,  was  required  in  the  main  lead  wires,  figuring 
no  losses.  Had  connection  been  made  to  the  110- volt  lighting  system, 
the  total  resistance  of  the  leads  and  detonators  would  require  to  be 
under  110  -f-  50.5,  or  2.2  ohms.  With  the  wiring  used  this  did  not 
leave  enough  margin  for  safety,  figuring  on  poor  joints,  etc.,  and  so 
connection  was  made  to  the  550-volt  circuit,  especially  as  no  instance 
had  been  noted  at  this  mine  where  excess  of  power  caused  any  trouble 
with  complete  detonation. 

In  connection  with  electrical  blasting,  care  must  be  taken  that  the 
resistances  in  the  various  circuits  are  well  balanced,  so  that  all  the  de- 
tonators will  explode  at  the  same  time.  The  best  way  to  insure  this  is 
to  use  large  lead  wires  and  to  take  care  that  the  same  number  of  de- 
tonators are  connected  up  in  each  series.  This  was  illustrated  in  a 
rather  forcible  manner.  On  one  occasion  a  small  blast  had  to  be  ex- 
ploded and  the  electrician  did  the  wiring  for  it.  He  had  been  instructed 
to  see  that  all  detonators  were  connected  up  in  even  series,  but  on  this 
occasion  there  were  101  holes  to  be  connected,  and  he  took  the  chance  of 
making  three  series  of  25  holes  and  one  series  of  26  holes,  the  last  series 
being  nearest  to  the  main  leads.  After  the  blast,  it  was  noticed  that 
the  three  series  of  25  holes  had  exploded,  but  the  series  of  26  holes  had 
failed  to  explode ;  fortunately  the  unexploded  holes  were  easy  to  rewire. 
It  was  considered  possible  that  if  the  speed  at  which  the  fuse  wires  in  the 
detonators  reach  the  detonating  temperature  was  less  than  the  speed 
of  explosion,  then,  given  suitable  conditions,  the  explosion  from  the 
series  of  25  could  break  the  lead  wires  of  the  series  of  26  before  the  fuse 
wires  in  these  detonators  had  reached  the  detonating  temperature,  and 
so  cause  the  failure  to  explode. 

Some  experiments  were  made  to  test  out  this  idea.  Two  detonators 
were  wired  in  series  and  one  lead  wire  was  wound  round  another  single 
detonator.  The  two  detonators  were  connected  through  one  circuit 
to  the  battery  and  the  single  detonator  through  another  parallel  circuit. 
When  fired,  the  single  detonator  exploded,  broke  the  lead  wire  around 
it,  and  the  other  two  detonators  failed  to  explode.  This  showed  that 
with  the  current  employed  the  speed  of  explosion  of  a  detonator  was 
greater  than  the  speed  of  heating  up  the  fuse  wire  in  a  detonator.  Similar 
results  were  obtained  by  connecting  up  in  this  manner  series  of  two  and 
three,  and  series  of  three  and  four  detonators.  It  is  possible  that  the 
failure  of  the  26  holes  to  explode  may  have  been  due  to  some  other 
cause,  but  the  experiment  showed  clearly  the  necessity  for  having 


EXPLOSIVES 


37 


well-balanced  circuits  with  the  same  number  of  detonators  in  series  in 
each  circuit. 

Sinking  with  Delay-Action  Fuses  (By  W.  V.  DeCamp). — The  some- 
what recent  development  of  the  electric  detonator  known  as  the  "  delay- 
action  fuse,"  placed  on  the  market  some  years  ago  by  the  Giant  Powder 
Co.  and  later  by  the  Du  Pont  company,  has  neither  the  disadvantages  of 
the  instantaneous  electric  detonator  nor  those  of  the  long  black-powder 
fuse,  subject  to  so  many  causes  of  failure.  The  delay-action  fuse,  Fig. 
36,  is  in  reality  an  electrical  means  of  spitting  holes;  for  it  consists  simply 
of  a  small  piece  of  gutta-percha  fuse,  on  one  end  of  which  is  placed  an 
ordinary  detonator,  and  on  the  other  a  cap  containing  the  igniting 
material.  Through  this  cap,'  terminal  wires  are  inserted  and  connected 
by  a  ribbon  or  sponge  of  low-fusion  material.  This  sponge  is  ignited  by 
the  passing  current  and  in  turn  ignites  the  fuse,  which  burns  to  the  cap 


LowFusion 
Sponge 


Detonator   Guttakrcha 
Fuse 


Insulation 
Terminals-. 


Jo220VoltLiqht 
Line 


FIG.    36.  -  DELAY-ACTION  DETONATOR  AND  SHAFT-WIRING  DIAGRAM. 


and  explodes  the  charge.  It  is  obvious  that  any  length  of  delay  can  be 
obtained  by  lengthening  the  piece  of  fuse.  The  entire  device,  fuse, 
detonator  and  ignition  cap,  is  incased  in  a  rubber  tube  and  coated  with 
a  good  waterproofing  paint.  The  terminal  wires,  where  they  enter  the 
ignition  cap,  are  also  incased  in  sulphur,  insuring  perfect  insulation. 
In  most  underground  work  only  three,  or  possibly  four,  delays  are  neces- 
sary. Each  fuse  with  terminal  wires  attached  has  a  tag  fastened  to  it, 
stating  its  number,  so  that  there  need  be  no  confusion  whatever  in 
loading  holes. 

A  thorough  trial  of  this  type  of  fuse  was  made  at  the  property  of  the 
Pacific  Copper  Mining  Co.,  Crown  King,  Ariz.,  and  it  resulted  in  a 
material  reduction  in  sinking  costs.  The  shaft  in  whicli  the  trial  was 
made  was  broken  about  7  X  10  ft.,  and  while  sinking  through  an  ex- 
tremely hard  siliceous  schist  a  large  volume  of  water  was  encountered; 
this,  with  the  small  dimensions  of  the  shaft  and  the  hard  rock,  greatly 


38  DETAILS  OF  PRACTICAL  MINING 

delayed  the  work;  20  to  24  holes  were  required  to  break  a  4-ft.  round; 
missed  holes  were  a  regular  occurrence  and  the  cost  became  almost 
prohibitive.  The  average  time  required  for  a  full  round  was  from  36  to 
48  hr.  and  the  average  depth  broken  was  4  ft.  During  the  month  previ- 
ous to  the  use  of  delay  fuses  the  daily  average  advance  was  2.1  ft.  The 
delay  fuses  were  used  on  the  last  48  ft.  of  shaft  sunk,  10  rounds  being 
required  in  this  distance.  Every  round  fired  was  satisfactory,  there 
being  only  two  missed  holes  in  the  entire  10  rounds. 

COMPARATIVE  COSTS  OF  SINKING  WET  SHAFT  WITH   AND    WITHOUT   DELAY-ACTION 

FUSES 

Ordinary  method;  Using  delay-action  fuses; 

depth  sunk,  63  ft.;  depth  sunk,  48  ft.; 

T    u  time,  30  days  time,  15  days 

Labor.  Total  Cost  Total  Cost 

cost  per  ft.  cost  per  ft. 

Miners $1210.75    $19.20  $617.50    $12.87 

Topmen 242.00        3.84  116.00        2.42 

Engineers 522.80        8.35  310.00        6.45 

Foreman 186.00        2.95  99.00        2.06 

Blacksmith  and  helper....      239.30        3.81  122.00        2.54 

$38.15  $26.34 

Power  supplies: 

Fuel  oil 648.00      10.30  402.00        8.38 

Lubricants 37.87        0.60  21.00        0.43 

Coal 35.50        0.56  16.20        0.33 

11.46  9.14 

Supplies : 

Machine  repairs 22.80        0.36  19.50        0.40 

Powder 194.00        3.09  91.50      .1.90 

Fuse 42.15        0.68  a24.00        0.50 

Caps 6.60       0.01 

Candles 34.75        0.56  612.10        0.25 

4.70  3.05 

Timbering : 

Setting 72.00        1.15  45.00        0.94 

Framing 63 . 00        1 . 00  46 . 50        0 . 97 

Timber 190.00        3.02  146.50        3.05 

5.17  4.96 

Water: 

Fuel  and  oil 139.50        2.22  210.50        4.37 

Pumping  labor 27.00        0.43  124.00        2.58 

2.67  6.95 


Total  .................................   $62.15  $50.44 

a  —  Electric  fuses. 


Operations  were  as  follows:  After  loading,  the  holes  were  connected 
in  series  and  thence  to  a  220-volt  direct-current  lighting  line  on  which 
there  were  two  switches,  one  at  the  nearest  level,  the  other  at  the  collar 


EXPLOSIVES  39 

of  the  shaft,  both  under  lock  and  key,  the  key  in  possession  of  the  boss. 
Three  different  lengths  of  fuse  were  used,  one  length  on  the  eight  cut- 
holes,  the  second  length  on  the  next  row  of  four  holes  on  each  side  and 
the  third  length  on  the  two  rows  of  end  holes,  as  shown  in  the  diagram, 
Fig.  36.  The  length  of  fuse  in  each  case  was  1.5  in.,  2  in.  and  3  in., 
respectively.  From  such  a  round  one  would  naturally  expect  to  get 
three  distinct  reports,  but  such  was  never  the  case.  There  would  be  from 
8  to  16  reports  for  the  entire  round;  the  reports  would  be  close  together 
and  sounded  much  like  the  rattle  of  a  bunch  of  firecrackers.  The  large 
number  of  reports  obtained  was  probably  due  to  the  fact  that  pieces  of 
fuse  of  the  same  length  would  not  burn  down  in  exactly  the  same  time, 
and  to  the  probable  difference  in  resistance  of  the  ignition  material  in 
different  caps,  thereby  requiring  a  slightly  longer  time  for  ignition. 

In  all  of  the  10  rounds  the  rock  was  broken  much  finer  than  had  been 
the  case  with  ordinary  fuse;  this  was  probably  due  to  the  rapid  succession 
of  the  explosions,  the  rock  mass  being  maintained  thereby  in  a  constant 
state  of  rapid  vibration,  resulting  in  greater  fracturing,  as  the  successive 
charges  would  explode.  The  average  depth  of  round  using  delay  fuses 
was  5  ft.,  the  average  depth  broken,  4.8  ft.,  and  the  average  time  for  each 
round,  36  hr. 

The  accompanying  table  shows  the  difference  in  cost  of  sinking  by 
the  two  methods.  It  will  be  seen  from  total  costs,  that  there  was  a  large 
increase  in  the  expense  of  handling  water,  also  an  increase  in  cost  of 
engineers,  due  to  some  heavy  repairs  made;  otherwise  the  costs  check 
up  fairly  well. 

Blasting  Box  for  Sinking  (Proceedings,  Lake  Superior  Mining  Institute). 
— A  device  which  is  ingenious  and,  so  far  as  known,  unique,  was  em- 
ployed in  sinking  the  Palms  shaft  of  the  Newport  Mining  Co.  It  was  a 
paraffin  pasteboard  box,  9  X  3^  X  1^  in.  deep.  In  the  sides  of  this 
box,  near  the  bottom,  holes  were  made  with  an  iron  punch  just  large 
enough  for  a  fuse  to  fit  snugly.  As  first  used,  a  positive  electric  wire  was 
led  through  one  end  and  a  negative  through  the  other,  and  the  ends  of 
these  connected  with  a  1-amp.  electric  fuse.  Two  of  the  boxes  were 
used  at  once  to  blast  the  cut,  which  consisted  of  about  40  holes.  From 
the  surface,  two  positive  wires  of  14-gage  copper  were  strung,  one  for 
each  box;  the  negative  wires  from  the  boxes  were  connected  to  the  air 
pipe.  After  fuses  of  proper  length  were  inserted  through  the  holes  in  the 
box,  a  small  quantity  of  F.  F.  rifle  powder  mixed  with  ordinary  black 
blasting  powder  was  strewn  over  the  1-amp.  fuse  and  the  box  was  covered 
with  a  wooden  lid.  When  the  men  reached  the  surface  they  tested  with 
a  galvanometer  to  find  out  whether  the  wire  connections  were  satis- 
factory when  the  circuit  was  closed.  Then  a  250-volt  current  was  thrown 
on  and  the  1-amp.  fuse  was  melted  so  that  the  powder  ignited,  and  in 


40  DETAILS  OF  PRACTICAL  MINING 

turn  ignited  the  fuses  leading  into  the  boxes.  The  cross  spitting  of  the 
fuses  across  the  boxes  made  it  almost  impossible  for  a  misfire  to  occur. 
The  lengths  of  the  fuses  were  adjusted  to  get  the  proper  sequence  of 
holes. 

It  was  found,  however,  that  the  preparation  of  the  1-amp.  fuse  box 
required  too  much  labor,  so  that  later  an  electric  blasting  squib  was 
used  to  ignite  the  powder  in  the  box.  A  squib  was  placed  through  a  hole 
in  each  end  of  the  box,  two  being  used  to  insure  igniting  the  powder, 
and  the  boxes  were  connected  in  series  with  only  one  No.  14  positive 
copper  wire  from  the  surface  and  with  a  single  negative  wire  connected 
to  the  air  pipe.  Finally,  a  Du  Pont  relay  electric  fuse  igniter  was  used 
and  connected  with  the  squib. 

Electric  Blasting  with  Dry  Battery  (By  C.  Carleton  Semple). — 
A  cheap  electric  blasting  apparatus  can  be  made  from  dry  batteries  such 
as  are  used  for  electric  call-bell  work.  Tests  show  that  at  least  two  caps 
can  be  detonated  for  each  cell  in  the  battery.  This  would  indicate  that 
a  battery  of  eight  cells  should  suffice  for  any  ordinary  drift  round.  The 
eight  cells  may  be  placed  in  a  wooden  box,  conveniently  in  two  rows  of 
four  cells  in  the  row.  The  cells  should  be  connected  in  series,  one 
battery  terminal  being  connected  to  one  of  two  binding  posts  placed 
near  together  at  one  end  of  the  box.  The  other  battery  terminal  should 
be  connected  to  the  center  of  a  two-point  switch  secured  to  the  end 
of  the  box  near  the  two  binding  posts.  One  point  of  the  switch  should  be 
connected  to  the  second  binding  post;  the  second  point  of  the  switch, 
not  being  connected,  is  the  off  position.  The  box  should  be  equipped 
with  a  substantial  hinged  cover,  preferably  locked  in  place,  and  a  stout 
strap  which  may  be  slung  over  the  shoulder  for  carrying  the  battery 
about. 

The  operation  is  simple.  The  switch  is  carried  on  the  off  or  blank 
point.  The  wires  from  the  round  are  secured  in  the  binding  posts  and 
when  ready  to  blast  the  switch  is  slipped  over  to  the  other  position. 
The  effect  is,  of  course,  instantaneous  unless  an  attempt  is  made  to  fire 
too  many  holes  for  the  number  of  cells  used.  While  the  flow  of  current  is 
.strong,  the  circuit  is  broken  so  quickly  by  the  detonation  of  the  charges 
that  the  dry  cells  should  recover  quickly  and  be  serviceable  for  a  long 
time. 

It  is  a  simple  matter  to  arrange  such  a  battery  so  that  the  circuit  may 
be  tested  by  sending  through  a  small  current  before  switching  on  the 
full  current  of  all  the  cells  in  series.  One  pound  of  No.  22  copper  magnet- 
wire,  wound  on  a  spool  for  convenience,  placed  in  the  circuit  of  only  one 
electric  detonator,  will  enable  one  to  send  the  current  of  one  dry  cell 
through  the  circuit  without  exploding  the  detonator.  If,  then,  the  bat- 
tery box  is  so  arranged  with  one  cell  in  circuit  with  such  a  spool  of  wire 


EXPLOSIVES  41 

/ 
for  resistance,  it  will  be  possible  to  arrange  a  three-point  switch  in  such  a 

manner  that  the  lead  wires  from  the  round  may  be  attached  to  the 
binding  posts  while  the  switch  is  on  the  blank  point.  Obtaining  a  spark 
at  the  switch  while  making  and  breaking  contact  with  the  second  point 
to  which  the  single  cell  and  coil  of  wire  is  connected,  would  indicate  a 
closed  circuit  which  will  be  fired  upon  throwing  the  switch  over  to  the 
third  point  to  which  all  the  cells  of  the  battery  are  connected.  A  still 
more  elaborate  device  can  be  made  by  placing  a  cheap  and  simple  gal- 
vanometer on  the  end  of  the  box  connected  with  the  second  point  of  the 
three-point  switch  and  the  one  cell  and  resistance  coil;  the  movement  of 
the  needle  would  then  indicate  a  closed  circuit  much  better  than  would 
sparking  at  the  switch. 

Fuse -cutting  Table  (By  Herbert  Gates). — To  facilitate  the  rapid 
cutting  of  fuse  to  any  desired  length  a  table,  illustrated  in  Fig.  37,  was 
devised.  The  board  A,  1%  X  12  in.  by  9  ft.,  is  erected  to  a  suitable  height 


FIG.    37. FUSE-CUTTING  TABLE  WITH  KNIFE,  PINS  AND  CLIP  CLAMP. 

and  the  cutting  block  B,  ^  X  %  X  6  in.,  fastened  near  one  support. 
The  knife  blade  C  is  hinged  to  the  block  at  one  end,  so  that  its  edge  will 
just  pass  the  side  of  the  block  and  make  a  clean  cut.  This  edge  should 
be  thin  and  beveled  like  a  wood  chisel.  The  adjustable  clamp  D  is 
fitted  with  a  thumbscrew,  so  that  it  can  be  shifted  to  give  the  desired 
length.  The  clip  on  the  end  has  teeth,  but  is  not  so  rough  that  the  fuse 
will  be  cut.  The  spool  G  is  3J^  in.  in  diameter  and  6^  in.  long,  built 
about  a  piece  of  J^-in.  pipe  and  closed  at  the  end  with  a  disk  7  in.  in 
diameter.  There  is  a  ^-m.  pin  E,  fastened  to  an  upright  and  a  wooden 
disk  F,  1  X  7  in.  In  operation,  the  coils  are  separated  into  the  small 
inner  coils  and  the  larger  outside  coils,  and  two  of  the  smaller  size  slipped 
over  E  and  held  on  by  F.  The  ends  are  brought  to  bear  against  the  up- 
right end  of  the  clamp  D,  and  the  clip  forced  down  upon  them.  The 
fuse  near  the  coil  is  held  on  the  block  B,  and  cut  with  the  hinged  knife. 
The  outside  coils  are  manipulated  by  putting  them  on  the  spool  G,  two 
at  a  time,  and  then  slipping  the  spool  on  the  pin  E. 


42 


DETAILS  OF  PRACTICAL  MINING 


Fuse-cutting  Bench  (By  S.  R.  Moore). — A  good  bench  used  at  the 
Success  mine  in  Idaho  is  shown  in  Fig.  38.  It  is  cheap  and  simple  and 
has  proved  satisfactory.  The  bench  is  3  X  9  ft.  Two  rollers,  one  2  in. 
and  one  4  in.  in  diameter,  are  mounted  at  one  end  to  hold  the  fuse  coil. 
One  of  the  bearings  for  each  roller  pin  is  slotted,  so  that  the  rollers  are 
easily  removable.  Across  the  opposite  end  of  the  bench  is  nailed  a 
1  X  2-in.  slat,  and  on  top  of  this  is  a  lever  made  of  1J^  X  2-in.  material, 
slightly  beveled  on  its  lower  edge,  with  a  weight  attached  to  its  handle; 
the  fulcrum  end  is  raised  just  the  thickness  of  a  fuse,  so  that  when  the 
weight  is  applied,  the  lever  bears  equally  upon  all  the  fuses  between  it 
and  the  slot.  A  chopping  block  of  2  X  4-in.  material  is  nailed  at  such  a 
distance  from  the  lever  as  to  give  the  desired  length  of  fuse,  and  in  such  a 
manner  as  to  be  easily  replaced  when  worn  out. 


FIG.    38. BENCH    WITH    ROLLERS,    CHOPPING   BLOCK    AND    WEIGHTED    LEVER. 


To  use  the  bench,  five  large  coils  are  placed  on  the  larger  roller,  and 
five  small  coils  on  the  smaller  roller.  It  is  found  that  by  piling  coils  on 
top  of  one  another,  and  pushing  the  roller  through  before  removing  the 
paper,  no  difficulty  is  experienced  from  the  coils  becoming  entangled. 
The  ends  of  10  fuses  are  placed  under  the  lever,  and  with  one  blow  of  a 
sharp  ax  on  the  chopping  block,  the  fuses  are  easily  cut  to  exactly  the 
same  length.  The  new,  evenly  cut  ends  are  again  placed  under  the 
lever  before  releasing  the  hold.  The  cut  fuses  are  rolled  in  coils  of  10 
each  with  the  ends  to  be  capped  sticking  out  slightly.  If  a  glancing  blow 
be  given  on  a  good  chopping  block  with  a  sharp  ax,  the  end  of  the  cut 
fuse  will  cap  better  than  when  cut  with  a  knife  and  equally  as  well  as 
when  cut  with  a  crimper.  With  a  little  practice,  500  fuses  can  be  cut, 


EXPLOSIVES 


43 


coiled  and  counted  in  a  hour,  as  compared  with  half  a  day  when  cut 
singly. 

Powder  Chutes  for  Openpits  (By  B.  M.  Concklin). — An  arrange- 
ment has  been  installed  in  several  of  the  openpits  upon  the  Mesabi 
range  for  the  purpose  of  saving  time  and  facilitating  the  distribution 
of  black  powder  to  points  within  the  pits.  The  device,  as  shown  in 
Fig.  39,  is  simple  in  itself,  consisting  of  two  greased  slides  in  which  run 


DETAIL  OF  SHEAVES  AND  BRAKE 


GENERAL  ARRANGEMENT  OF  CHUTE 


FIG.    39. APPAEATUS  FOR  LOWERING  POWDER  INTO  OPENPITS. 

two  triangular-shaped  boxes  made  to  carry  from  four  to  six  kegs  of 
black  powder,  and  an  arrangement  of  sheaves  at  the  top  of  the  slides 
as  shown  in  the  accompanying  engraving.  The  operation  is  accom- 
plished by  means  of  gravity,  the  loaded  box  carrying  the  empty  one 
to  the  top.  The  speed  is  regulated  by  means  of  the  brake  shown. 
Where  the  pits  are  deep  and  the  lower  levels  are  inaccessible,  except  by 
long  and  steep  climbs,  this  contrivance  has  been  the  means  of  a  con- 
siderable saving  of  time  and  money  as  well  as  acting  as  a  safety  device 


44 


DETAILS  OF  PRACTICAL  MINING 


for  the  prevention  of  possible  explosions  when  the  powder  is  thrown 
over  the  banks  into  the  pits. 

Bag  for  Carrying  Dynamite  (By  W.  R.  Hodge). — In  the  Burra  Burra 
mine  of  the  Tennessee  Copper  Co.,  it  is  often  necessary  to  carry  a  box 
of  powder  up  or  down  150  ft.  of  ladders  to  get  it  into  a  back  stope.  The 
bag  illustrated  in  Fig.  40,  has  been  devised  to  make  easier  the  trans- 
portation of  dynamite  through  the  manways.  The  bag  is  of  canvas, 
reinforced  by  a  double  strip  of  the  same  material  on  the  bottom  and 
ends.  At  the  top  of  each  end  the  strip  is  doubled  over  and  riveted  about 
an  iron  ring  to  which  is  snapped  the  shoulder  strap.  This  strap  is  of 
leather  2  in.  wide  and  3  ft.  long,  provided  with  a  harness  snap  at  each 
end.  The  bag  is  divided  by  a  canvas  partition  down  the  middle,  making 
compartments  a  little  longer  than  a  stick  of  dynamite.  A  canvas  flap 


-1 

o      o 

J= 

t 

i 

i 

U -*»-- ->! 

FIG.    40. CANVAS  BAG  TO  HOLD  50  LB.  OF  DYNAMITE. 

secured  by  two  straps  and  buckles  covers  the  top  of  the  bag.  All 
seams  and  edges  are  leather  bound.  The  capacity  of  the  bag  is  about 
one  case  of  dynamite.  By  its  use  the  hands  are  left  free  for  the  lad- 
ders, while  in  the  stope  the  powder  is  readily  accessible  for  distribution. 


STORAGE  AND  THAWING 

Electric  Heating  for  Primer  House  (By  E.  P.  Kennedy). — At  the 
Treadwell  mines  on  Douglas  Island,  southeastern  Alaska,  it  has  always 
been  the  custom  to  make  up  the  primers  in  houses  on  the  surface.  There 
were  three  such  primer  houses,  all  heated  by  stearn.  Recently  a  central 
primer  house  was  built,  in  which  the  primers  of  all  the  mines  are  made. 
This  primer  house,  illustrated  in  Fig.  41,  is  situated  1600  ft.  from  the 
nearest  boilers  and  about  1  mile  from  the  Treadwell  mine.  Four 


EXPLOSIVES 


45 


1    " 

1 

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CJ 

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Primer      Table 

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|| 

M 
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vl 

i 

op 

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5% 

00 

Fuse  |  \Cutter 

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i"j       Jg 

«5                  rH 

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PLAN 

Ab./!?  <5o/K  (Tor/:  Iron-^ 
rsheathing- 


g  Matched  Flooring.  \ 
P&B.  Paper^  \  ! 
/  Rough  Floor.  X  t  V 


CROSS   SECTION 
FIG.    41. ALASKA-TREADWELL  PRIMER  HOUSE. 


46  DETAILS  OF  PRACTICAL  MINING 

sectional  steam  radiators  were  installed,  but  instead  of  connecting  with 
steam,  a  3000-watt  Westinghouse  bayonet  heater  was  screwed  into 
the  bottom  of  each  radiator.  A  short  pipe  was  tapped  into  the  top  of 
the  radiator  and  connected  with  a  small  covered  tank,  which  was  kept 
full  of  water,  a  small  amount  being  added  when  necessary  to  take  care 
of  the  evaporation.  All  leads  entering  the  building  and  connecting 
with  the  bayonet  heaters  are  in  conduit  and  all  switches  are  situated 
outside  the  building.  The  four  radiators  proved  ample  for  the  coldest 
weather  and  the  amount  of  radiation  can  be  regulated  by  opening  the 
switch  for  one  or  more  of  the  radiators.  The  installation  has  proved 
most  satisfactory.  From  the  point  of  safety  it  appears  to  be  above 
criticism  and  as  there  is  no  loss  of  energy  it  would  probably  prove  more 
economical  for  an  isolated  place  than  a  long  steam  line  from  which  there 
is  continual  leakage  and  radiation. 

Each  primer  consists  of  a  4-in.  stick  1J^  in.  in  diameter  of  70  per 
cent,  nitroglycerin  powder;  the  caps  are  6X  and  the  fuse  is  securely 
tied  to  the  primer.  In  .the  course  of  one  year  there  are  875  miles  of 
fuse  cut  up  into  2-,  6-  and  9-ft.  lengths,  capped,  inserted  and  securely 
fastened  into  877,000  sticks  of  powder.  One  man  in  charge  and  two 
natives  can  keep  all  the  mines  supplied  with  primers. 

Magazine  for  Storing  and  Thawing  (By  Claude  T.  Rice). — In  Fig. 
42  are  shown  the  details  of  construction  of  the  magazine  used  by  the 
St.  Louis  Smelting  &  Refining  Co.  In  choosing  a  site  for  this  magazine 
a  hollow  was  selected;  hence  there  is  practically  no  possibility  of  shoot- 
ing into  the  magazine  except  by  malicious  intent.  The  site  is  several 
hundred  yards  away  from  any  other  building.  The  dynamite  is  thawed 
in  the  boxes  without  any  unnecessary  handling.  This  makes  the  thawing 
cheaper  and  less  dangerous,  for  at  every  point  where  dynamite  is  handled 
there  is  a  source  of  danger,  while  the  headache  that  results  from  un- 
packing and  repacking  is  not  desirable.  Thawing  .houses  in  which  it 
is  necessary  to  take  the  dynamite  out  of  the  boxes  pay  only  when  the 
amount  used  each  day  is  small.  The  thawing  house  for  a  large  mine 
should  be  large  enough  to  hold  at  least  a  week's  supply,  since  then  the 
thawing  can  be  done  slowly.  Consequently,  it  is  just  as  well  to  do  the 
thawing  in  the  magazine  itself  as  in  a  separate  place. 

It  will  be  noticed  from  the  drawings  that  there  is  a  partition  P  of 
2-in.  planks  carried  on  studding  of  2  X  6-in.  lumber  built  out  3  ft.  from 
the  walls,  inside  which  the  dynamite,  still  in  the  original  boxes,  is  piled. 
To  enable  air  to  circulate  around  them,  the  boxes  are  piled  with  ^  X  2- 
in.  strips  between.  A  small  space  is  also  left  between  the  vertical  rows 
of  the  piles.  As  the  air  is  free  to  circulate  it  requires  only  about  three 
days  to  thaw  frozen  dynamite  in  the  box  when  the  temperature  of  the 
thawing  room  is  kept  at  70°  F.,  while  one  winter  with  the  thermometer 


EXPLOSIVES 


47 


48  DETAILS  OF  PRACTICAL  MINING 

outside  15°  below  zero  and  the  magazine  around  55°,  it  took  only  about 
five  days  to  do  the  thawing.  With  the  boxes  piled  in  this  manner 
there  is  room  for  storing  about  40  tons  of  dynamite. 

Hot  water  is  used  for  heating.  Owing  to  the  slatted  partitions  and 
the  fact  that  the  radiators  R  are  placed  close  along  the  sides  of  the  build- 
ing, the  dynamite  can  be  placed  within  3  ft.  of  the  water  pipe.  The  hot 
water  is  generated  in  a  Tabasco  No.  21  heater  which  is  directly  connected 
to  the  water  pipes  without  any  temperature-regulating  mechanism 
on  the  heater,  for  it  is  impossible  to  heat  the  magazine  above  a  tempera- 
ture of  70°  in  ordinary  winter  weather.  The  heater  house  is  placed  79 
ft.  away  from  the  magazine.  The  hot  water  is  carried  to  the  magazine 
in  pipes  incased  in  asbestos  pipe  covering.  Anthracite  is  used  to  fire 
the  heater. 

Both  the  heater  building  and  the  magazine  are  placed  on  concrete 
foundations.  The  walls  of  both  are  made  of  brick  and  corrugated  iron 
is  used  for  the  roofing  laid  on  top  of  1-in.  planking.  A  ceiling  C  of  1  X  3- 
in.  lumber  is  carried  across  the  building  even  with  the  tops  of  the  side 
walls  so  that  ample  air  space  is  left  above  the  dynamite  to  keep  the  maga- 
zine cool  in  summer.  This  air  space  is  connected  with  air  holes  H,  but 
in  winter  these  are  kept  closed.  The  floor  is  made  of  1  X  3-in.  planks, 
and  there  are  air  holes  V  connecting  with  the  space  under  the  floor  as 
well  as  others  /,  coming  in  just  at  the  level  of  the  floor.  These  air  spaces 
are  arranged  so  that  it  would  be  difficult  for  a  malicious  person  to  insert  a 
burning  piece  of  oily  waste  in  the  magazine.  Owing  to  the  ceiling,  it  is 
impossible  to  pile  the  dynamite  higher  than  the  brick  walls  that  protect 
it  from  bullets.  To  prevent  chilling  the  magazine  while  dynamite  is  being 
put  in  or  taken  out,  double  doors  are  provided.  These  are  lined  with 
sheet  iron  to  prevent  the  entrance  of  bullets. 

According  to  the  Missouri  law  the  dynamite  supply  in  the  mine  may 
not  be  more  than  enough  to  last  24  hr.  Consequently,  the  dynamite  has 
to  be  taken  from  the  magazine  to  the  different  shafts  each  day.  This  is 
done  by  placing  the  boxes  of  thawed  dynamite  in  a  transfer  box,  built  - 
with  double  walls,  of  2-in.  planks  so  as  to  provide  an  air  space  2  in.  wide 
all  around  the  box.  This  box  has  low  wheels  attached  to  it  and  travels 
along  a  track  of  1  X  6-in.  iron  nailed  to  the  floor  of  the  magazine  and 
extending  out  on  the  covered  porch  or  entry;  this  is  arranged  so  that  it 
just  comes  even  with  the  bed  of  an  ordinary  wagon  in  which  the  dynamite 
is  hauled  to  the  several  shafts.  This  transfer  box  is  made  so  as  to  hold 
about  30  boxes  of  dynamite,  which  is  ample  supply  for  one  day  at  these 
mines.  The  dynamite  does  not  freeze  in  the  box  even  with  the  ther- 
mometer down  to  16°  below  zero  in  the  open.  At  the  several  shafts  the 
number  of  boxes  of  dynamite  that  are  required  are  taken  out  of  the  trans- 
fer box  and  the  cover  replaced  instantly.  This  thawed  dynamite  is  at 


EXPLOSIVES  49 

once  placed  on  the  cage  and  lowered  to  the  underground  magazines 
before  it  .has  a  chance  to  freeze.  The  transfer  box  when  empty  is  returned 
to  the  magazine  and  placed  inside  it  again  so  that  it  will  be  warm  when 
the  dynamite  is  loaded  into  it  next  day.  This  magazine  was  built 
according  to  the  directions  of  George  A.  Allen,  of  the  Aetna  Powder  Co. 

Around  the  magazine  and  at  a  suitable  distance  is  a  picket  fence  6 
ft.  high.  Between  the  fence  and  the  magazine  and  outside  the  fence  for 
a  distance  of  10  ft.  is  a  deep  layer  of  tailings  designed  to  prevent  any 
brush  fires  Jrom  reaching  the  magazine. 

Suitable  Powder  Magazines. — A  dugout  in  the  side  of  a  hill  is  often 
considered  a  good  place  in  which  to  store  explosives.  This,  however,  is 
a  mistake,  and  such  a  magazine  is  ultimately  an  expensive  one,  because  the 
efficiency  of  the  explosive,  on  account  of  its  moisture-absorbing  proper- 
ties, falls  off  rapidly  when  stored  underground  for  any  length  of  time. 
Powder  magazines  should  be  constructed,  and  a  good  material  is  brick. 
Stone  or  solid  concrete  or  similar  materials,  which  in  the  event  of  an 
explosion  would  be  converted  into  projectiles,  and  do  damage  to  surround- 
ing property,  should  not  be  used.  Brick  is  pulverized  into  dust  by  a 
dynamite  explosion  and  does  no  harm.  Powder  magazines  should  have 
bullet-proof  doors,  arid  where  this  is  not  feasible  the  doorways  should  be 
protected  by  a  screen  or  barricade.  It  is  advisable  to  surround  the  entire 
magazine  with  a  similar  barricade.  It  requires  11  in.  of  sand  to  stop  a 
bullet  fired  at  ordinary  range  from  a  modern  high-power  rifle  using  smoke- 
less powder,  such  as  is  commonly  used  now  by  hunters.  As  has  often 
been  suggested  before,  to  sink  the  entire  building  behind  a  heavy  earthen 
parapet  is  the  safest  method.  Then  anything  which  can  be  converted 
into  a  projectile  by  an  explosion  must  travel  with  a  high  trajectory  in 
order  to  do  any  damage. 

Electric  Powder  Thawer,  Underground  (By  A.  J.  Hewitt). — A 
suitable  place  for  a  powder-thawing  house  is  often  difficult  to  find, 
particularly  after  the  prospecting  stage  is  passed  and  the  plant  begins 
to  extend  so  as  to  cover  the  surface  with  buildings,  some  of  which  are 
sure  to  be  in  too  close  proximity  to  the  surface  thawing  house.  This 
was  the  case  at  the  property  of  the  Beaver  Consolidated  Mines,  Ltd., 
of  Cobalt.  After  considerable  study  and  careful  consideration  the  follow- 
ing solution  of  the  difficulty  was  adopted :  In  the  underground  workings 
of  the  mine,  on  the  200-ft.  level,  there  was  an  unused  drift,  the  heading  of 
which  was  about  800  ft.  from  the  main  working  shaft.  In  this  heading  a 
powder-thawing  cabinet  was  situated  and  as  heating  with  steam  was  out 
of  the  question,  owing  to  condensation,  a  small  inexpensive  electric  heater 
was  installed. 

The  construction  of  the  thawing  cabinet  is  simple,  as  can  be  readily 
seen;  Fig.  43  shows  the  front  elevation,  Fig.  44  the  side  and  Fig.  45  the 

4 


50 


DETAILS  OF  PRACTICAL  MINING 


plan.  The  cabinet  is  composed  of  three  tiers  of  racks,  each  rack  being 
large  enough  to  contain  60  sticks  of  dynamite.  The  racks  are  made  with 
slat  bottoms,  the  slats  being  close  enough  together  so  that  it  would  be 
impossible  for  a  stick  of  powder  to  fall  through,  at  the  same  time  permit- 
ting the  warm  air  to  come  into  contact  with  the  under  layer  of  powder  in 
the  rack.  There  is  also  an  air  space  left  at  the  sides  of  each  tier  of  racks- 


FIG.    43. FRONT  ELEVATION. 


FIG.    44. SIDE  ELEVATION. 


to  allow  the  heat  to  ascend  and  warm  the  entire  interior  of  the  cabinet. 
Warm  air  is  conveyed  to  the  thawing  cabinet  through  an  ordinary  stove 
pipe  well  wrapped  with  1-in.  hair  felt  and  cased  with  1-in.  lumber.  This 
air  duct  enters  the  cabinet  bottom  at  the  center,  as  shown  in  Fig.  44. 
Small  vents  are  present  in  the  top  of  the  cabinet  to  create  a  draft,  drawing 
warm  air  continually  from  the  heater.  The  electric  heater  is  a  wooden 


Center  line  of  drift 
in  which  fuse  and 
caps  are  store* 


FIG.    45. PLAN 

UNDERGROUND    ELECTRIC   THAWER,    BEAVER    CONSOLIDATED    MINES. 

box  covered  with  zinc,  in  which  are  placed  six  32-c.p.  lamps.  One  end  of 
the  box  is  made  to  slide,  and  is  used  to  regulate  the  draft  in  a  way  similar 
to  the  front  damper  of  an  old-fashioned  box  stove.  In  the  other  end  of 
the  box  near  the  top  a  hole  is  made  for  the  stove  pipe,  which  extends  about 
8  ft.  to  connect  with  the  thawing  cabinet. 


EXPLOSIVES 


51 


The  thawing  cabinet  is  situated  at  the  face  and  about  10  ft.  back  there 
is  a  tight  partition .  Outside  of  this  partition  the  electric  heater  and  electric 
light  are  installed,  all  wiring  being  carefully  insulated  and  none  extending 
through  the  partition.  The  electric  light  is  allowed  to  shine  into  the 
thawing  room  through  a  small  glass  window.  Access  to  the  thawing 
room  is  obtained  through  a  door  in  the  partition.  About  25  ft.  back 
from  the  thawing  room  in  a  short  crosscut  there  is  partitioned  off  a  small 
room  in  which  a  daily  supply  of  fuse  and  detonators  is  kept.  In  this 


FIG.    46. POWDER  THAWER  DISASSEMBLED. 

room  all  orders  for .  powder  are  taken  care  of  and  distribution  made  to 
the  different  parts  of  the  mine. 

Hot-water  Powder  Heater. — The  powder  heater  shown  in  Fig.  46 
is  used  throughout  the  iron  mines  at  Mineville,  N.  Y.  Due  to  the  low 
temperature  in  the  mines  even  during  the  summer  months,  the  powder 
must  be  thawed  except  for  a  certain  percentage  of  nonfreezing  powder. 
In  using  the  heater  shown,  the  fire  is  first  kindled  in  the  firebox,  the  water 
container  is  placed  over  the  firebox,  resting  on  corner  angles,  and  then 
the  cover  is  slipped  over  the  water  container.  The  latter  is  17  X  18 
in.  by  15  in.  high  and  made  on  the  principle  of  a  return-tubular  boiler. 
Flues,  18  in  number  and  2%  in.  in  diameter,  are  fitted  in  two  opposite 


52 


DETAILS  OF  PRACTICAL  MINING 


faces  of  the  container;  each  will  hold  six  sticks  of  1J£  X  8-in.  powder, 
making  the  capacity  of  the  box  108  sticks.  Water  is  poured  in  the  top 
of  the  container  until  it  is  well  above  the  top  row  of  tubes.  After  the 
water  has  been  heated  to  a  temperature  which  the  hand  will  bear,  the 
container  and  cover  are  removed  to  a  safe  distance  from  the  firebox  and 
the  fire  completely  extinguished.  The  cover  is  then  removed,  the  flues 
are  filled  with  the  sticks  of  powder  and  the  cover  replaced.  In  a  short 
time  the  powder  will  be  sufficiently  soft  for  use. 

Manure  Powder  Thawer. — A  satisfactory  arrangement,  utilizing  the 
heating  power  of  fresh  horse  manure  for  thawing  frozen  dynamite,  is 
used  underground  at  Mineville,  N.  Y.,  by  Witherbee,  Sherman  &  Co., 
Inc.  The  thawer,  as  shown  in  Fig.  47,  has  a  capacity  of  eighteen  50-lb. 
cases,  and  is  nothing  more  than  double  box  built  of  2-in.  planks  with  an 


PIG.    47. — HORIZONTAL  SECTION  THROUGH  MANURE-WARMED  THAWING  BOX. 


8-in.  space  between  the  outer  and  inner  boxes,  this  space  being  filled  with 
manure.  A  double  lid,  also  filled  with  manure,  is  used  and  the  bottom 
of  the  inner  box  is  similarly  filled,  so  that  the  powder  is  surrounded 
on  all  sides,  top  and  bottom  by  the  heating  material.  One-inch  holes  are 
bored  through  the  inner  box  into  the  manure-filled  spaces  to  permit 
circulation  of  the  heated  air.  The  powder  may  be  put  into  the  thawer 
while  in  its  original  boxes  or  the  sticks  may  be  put  in  loosely,  which 
enables  it  to  thaw  a  little  more  quickly.  Where  loose  sticks  are  placed 
in  the  thawer  and  different  strengths  of  powder  are  used,  it  will  be  found 
convenient  to  make  vertical  partitions  in  the  inner  box,  so  that  the 
different  grades  will  not  become  mixed.  It  has  been  found  that  when 
the  manure  is  fresh,  the  temperature  of  the  inner  box  may  become 
as  high  as  110°  F.  This  arrangement  does  away  with  all  the  dangers 
and  inconveniences  of  any  other  type  of  thawer  and  has  been  found 
satisfactory. 


EXPLOSIVES 


53 


SAFETY  PRECAUTIONS 

Methods  of  Making  Primers  (By  William  W.  Jones). — No  entirely  sat- 
isfactory method  of  constructing  a  dynamite  primer  has  heretofore  been 
available.  Of  the  various  methods  of  inserting  the  cap  in  the  cartridge, 
some  of  the  most  unsatisfactory  are  here  illustrated,  Fig.  48.  In  1  and 
2,  the  fuse  is  shown  laced  through  the  cartridge.  The  lacing  of  1  is 
perhaps  the  more  objectionable  of  the  two.  The  following  disadvan- 
tages, however,  attend  either  method:  (1)  The  dynamite  is  likely  to 
ignite  as  a  result  of  the  powder  train  in  the  fuse  burning  through  its  cov- 
ering at  some  point  in  the  cartridge  and  igniting  the  latter,  which  causes 


6  -7 

FIG.    48. UNSATISFACTORY  METHODS  OF  MAKING  PRIMERS. 

an  imperfect  explosion;  (2)  the  powder  train  is  likely  to  break  where  the 
fuse  is  bent  at  an  acute  angle,  causing  a  misfire;  (3)  the  diameter  of  the 
primer  is  so  increased  that  it  cannot  always  be  pressed  down  on  the  rest 
of  the  charge  and  the  resulting  air  gap  may  intercept  the  transmission  of 
the  explosion  so  that  the  inner  part  of  the  charge  is  not  exploded ;  (4)  the 
cap  does  not  point  along  the  charge  and  so  loses  part  of  its  efficiency, 
and  if  thrust  in  too  far,  it  is  liable  to  penetrate  the  opposite  side  of  the 
cartridge  and  be  exploded  by  scraping  on  the  rock. 


54 


DETAILS  OF  PRACTICAL  MINING 


In  3  and  4,  the  cap  inserted  at  an  angle  does  not  give  the  most  efficient 
detonation,  and  not  being  tied,  it  can  easily  pull  out.  In  3,  either  end 
may  project,  and  thus  cause  a  premature  explosion.  The  same  objection 
applies  to  5,  except  that  the  tying  tends  to  prevent  the  cap  from  pulling 
out.  Tying  is  often  neglected,  however,  as  it  takes  time,  and  string  is 
not  always  handy.  In  6,  the  detonator  points  in  the  proper  direction, 
but  not  being  tied,  is  easily  pulled  out.  In  this  case,  the  ends  of  the 
paper  wrapping  can  be  unfolded  and  tied  around  the  fuse  with  a  string, 
but  as  stated,  tying  is  frequently  neglected. 

In  7  is  shown  perhaps  the  most  commonly  used  way  of  priming 
with  an  electric  detonator;  it  is  open,  however,  to  two  objections:  The 
business  end  of  the  detonator,  if  the  primer  be  on  top  as  usual,  points 
outward  instead  of  into  the  bulk  of  the  charge,  and  the  half-hitches  are 
likely  to  damage  the  insulation.  In  8,  the  detonator  does  not  point  to  the 


FIG.    49. NEW  METHOD  OF  CONSTRUCTING  PRIMER. 

best  advantage  and  is  liable  to  project  on  one  side.  Furthermore,  in 
tightening  the  half-hitch  around  the  cartridge,  the  sulphur  plug  may  pull 
out  of  the  detonator  and  cause  an  explosion. 

It  will  be  noted  that  the  principal  objections  to  the  methods  of 
priming  here  illustrated  are  that  the  cap  is  not  placed  to  do  its  work  most 
efficiently,  or  it  is  likely  to  be  pulled  out,  causing  a  misfire,  or  it  is  liable  to 
premature  explosion.  A  recently  invented  and  patented  device  illus- 
trated in  Fig.  49  will  largely  do  away  with  these  objections  and  should 
be  a  great  aid  in  reducing  the  number  of  explosive  accidents.  It  permits 
the  insertion  of  the  cap  in  the  most  efficient  manner,  while  practically 
eliminating  the  danger  of  pulling  it  out  or  of  breaking  the  fuse  or  wires. 
It  consists  of  an  anchoring  device,  a  piece  of  string  with  a  knot  on  the 
end,  to  take  the  pull  on  the  fuse  or  wires  and  relieve  the  cap  itself  -of 


EXPLOSIVES 


55 


tension.  A  double  cord  is  used  and  a  clove  hitch  taken  over  the  fuse  or 
the  wires.  The  method  of  doing  this  is  evident  from  the  drawing.  The 
cord  must  be  included  in  the  powder  stick  when  it  is  manufactured. 
It  is  evident  that  in  using  this  device  there  is  little  or  no  danger  of  the 
caps  pulling  loose  from  the  cartridge,  and  this  simple  fact  makes  it  possible 
to  place  the  cap  in  the  safest  and  most  efficient  position. 

Blasting  Bulletin  Board. — The  accompanying  form,  Fig.  50,  shows  the 
blasting  bulletin  board  used  at  the  shaft  stations  of  the  St.  Louis  Smelting 
&  Refining  Co.  in  the  Flat  River  district  of  Missouri.  As  the  men  go  off 
shift,  they  mark  in  the  proper  place  on  the  record  on  the  bulletin  the 
holes  j ust  fired.  The  driller  is  designated  by  name  as  well  as  by  the  number 
of  his  machine.  Thus  a  driller  on  the  next  shift  knows  by  the  number 
of  the  machine,  if  he  does  not  know  the  name  of  the  man  using  his  machine 
on  the  other  shift,  the  number  and  kind  of  holes  that  were  blasted  in  his 
working  place  on  the  preceding  shift. 


BLASTING  BULLETIN  BOARP 


Shift  B 

Shift  Boss...  . 
Holes  Fired 

Holes  Fired 

Breast 

Stope 

Lifter 

Name  of  Driller 

Number 
of 
Drill 

Name  of  Driller 

Breast 

Stope 

Lifter 



Special  Instructions 


It  is  the  duty  of  the  drillers  and  backhands  to  study,  this  bulletin  carefully  before  going  to  work  and 
upon  arriving  at  their  respective  places  .of  work  to  make  a  thorough  search  for  missed  holes. 
All  missed  holes  must  be  fired  before  drilling  is  started. 

FIG.    50. ST.  LOUIS  SMELTING  &    REFINING  CO.  BLASTING  REPORT. 

The  method  of  designating  the  holes  will  differ  according  to  the 
method  of  breaking  ore.  The  object  in  giving  the  names  of  the  holes  is 
that  by  such  a  system  the  men  can  take  care  against  drilling  into  missed 
holes.  When  so  many  men  are  blasting  in  the  mine  it  is  impossible  to 
count  the  holes  and  determine  those  of  each  man.  Even  when  it  is  im- 
possible for  each  miner  to  stop  in  a  place  where  he  can  tell  from  the  reports 
whether  his  are  the  holes  exploding,  it  is  well  to  make  each  driller  chalk 
under  such  a  bulletin  board  the  kind  of  holes  that  he  has  fired  and  the 
number.  It  makes  the  work  of  the  driller  safer,  and  less  time  is  lost  by 
the  miner  on  the  next  shift  in  looking  over  the  breast  to  make  sure  that 
there  are  no  cut-offs  or  missed  holes. 


56 


DETAILS  OF  PRACTICAL  MINING 


Form  for  Missed-hole  Reports  (By  B.  H.  Smith). — An  ingenious 
method  for  reducing  the  probability  of  missed-hole  accidents  was  adopted 
in  sinking  the  Monarch-Pittsburgh  shaft,  at  Tonopah.  The  idea  is  not 
entirely  new,  having  been  used  in  the  Coeur  d'Alenes  previously.  A  blank 
form,  as  shown  in  Fig.  51,  was  placed  in  a  conspicuous  place  of  the  change 
house,  and  in  the  rectangle  a  plan  of  the  holes  in  the  shaft  bottom  was 
made.  The  shift  coming  off  after  blasting,  marked  rings  around  the  dots 
representing  the  holes  which  it  was  suspected  had  missed,  and  each 


FAILURE  TO  MARK  AND  SIGN  REPORT  WILL  BE  CAUSE  FOR  IMMEDIATE  DISMISSAL 

MISSED  HOLE  REPORT 
MONARCH-PITTSBURG  EXTENSION  MINING  COMPANY 

SHIFT                                       TO 

SHAFTMEN  WILL  MARK  HOLES  BELIEVED  TO  HAVE  MISSED  FIRE.  IN  DIAGRAM  BELOW 
CRAW  A  C  RCLE  AROUND  MISSED  HOLES 

N 

.                   .                 Q 
£        •                   •                     . 

•     G> 

'         ©      •        « 

TOTAL  MISSED  HOLES-iJ?  

SIGN  HERE 

ON  COMING  SHIFT 

FIG.    51. FORM  FILLED  OUT  TO  SHOW  THREE  HOLES  MISSED. 

member  of  the  shift  signed  below.  The  shift  coming  on  also  signed  at 
the  bottom  as  an  indication  that  each  member  had  examined  the  diagram. 
Two  purposes  were  served  by  this  device.  (1)  The  new  shift  was  forced 
to  receive  information  of  the  possibly  dangerous  holes;  (2)  the  liability 
of  the  company  to  damage  suits  was  decreased,  since  the  signatures  of 
the  men  would  show  that  they  were  aware  of  the  presence  of  the  danger. 
The  usual  method  of  leaving  the  record  of  suspected  holes  on  a  black- 
board for  the  new  shift  to  read,  is  never  satisfactory.  The  shift  which 
has  just  blasted  is  usually  in  too  much  of  a  hurry  to  chalk  up  the  missed 


EXPLOSIVES  57 

holes  and  the  shift  coming  on  frequently  does  not  bother  to  read  anything 
that  has  been  written. 

Neutralizing  Blasting  Fumes  (By  W.  H.  Mawdsley). — The  sulphur 
fumes,  caused  by  the  ignition  of  pyritic  ore  in  blasting,  are  in  some  mines 
exceptionally  severe;  in  such  cases  the  charges  are  usually  fired  only  at 
intervals  when  work  in  other  parts  of  the  mine  has  ceased.  A  simple 
and  effective  way  of  overcoming  this  difficulty,  as  well  as  that  caused  by 
the  fumes  from  the  explosive  itself,  is  by  the  use  of  suitable  chemicals  as 
tamping.  The  alkaline  hydrates  give  the  desired  results  and  also  absorb 
some  of  the  CO2;  the  addition  of  an  oxidizing  agent  in  the  tamping  con- 
verts the  CO  into  C02  which  can  then  be  absorbed.  With  regard  to  sul- 
phur fumes,  moist  slaked  lime  has  proved  invariably  effective.  A  small 
quantity  is  placed  at  the  bottom  of  the  hole  and  more  is  used  on  top  of  the 
charge  in  place  of  the  usual  clay  "  cocks. "  At  the  instant  of  explosion 
the  hydrate  comes  in  contact  with  the  nascent  gases  and  immediately 
absorbs  them.  Another  method  is  first  to  pour  a  little  water  into  the 
hole  and  then  add  some  soluble  hydrate  (such  as  barium  or  strontium) 
which  is  dissolved  in  the  water;  the  charge  is  now  introduced,  the  solution 
being  thus  mixed  in  with  the  explosive.  A  further  quantity  of  hydrate  is 
used  above  the  charge  in  place  of  the  ordinary  tamping.  The  material 
is  made  into  suitably  sized  cartridges  covered  with  as  little  paper  or 
organic  matter  as  possible.  This  tamping  is  a  convenience  to  the  miner, 
and  by  preventing  the  sulphur  fumes,  makes  blasting  in  pyritic  ore  possi- 
ble at  all  times.  By  the  addition  of  an  oxidizing  agent,  the  carbon  mon- 
oxide given  off  by  some  explosives  is  to  a  large  extent  rendered  innocuous. 


Ill 

ROCK  DRILLS 
Drilling  Kinks — Machine  Supports — Maintenance 

DRILLING  KINKS 

Drilling  Mesabi  Gopher  Holes. — Blasting  in  the  Mesabi  openpits  is 
necessary  in  stripping  if  the  overburden  is  somewhat  consolidated,  and 
rather  general  in  mining  unless  the  ore  is  unusually  soft.  Two  methods 
of  drilling  and  blasting  are  in  use.  One  consists  of  drilling  deep  down- 
holes  at  the  top  of  the  bench,  using  a  jumper  drill,  often  with  several 
men,  chambering  the  bottom  with  dynamite  and  blasting  with  black 
powder;  the  other  is  given  the  wholly  indefinite  name  of  " gopher-holing," 
a  term  which  has  a  different  signification  in  every  mining  region. 

Gopher-holing  here  consists  of  working  out  an  inclined  hole  about  16 
to  20  ft.  deep,  beginning  at  the  bottom  corner  of  the  bank  and  extending 
in  at  an  angle  of  10  to  20°  below  the  horizontal.  This  is  accomplished  in 
various  manners.  In  the  cases  observed,  a  set  of  tools  similar  to  that 
illustrated  in  Fig.  52  was  employed.  In  addition  to  these,  an  ordinary 
hand  auger  was  used  to  start  the  hole  and  take  out  the  first  few  feet; 
this  hole  was  blasted  with  a  stick  or  two  of  dynamite,  the  effect  being 
to  leave  a  long  bootleg  of  8  to  14  in.  in  diameter.  The  auger  being 
unwieldy  in  deep  holes,  a  long  moil-pointed  bar  usually  of  IJ^-in.  steel 
was  next  brought  into  service,  shown  in  the  illustration.  This  was  driven 
into  the  bottom  of  the  bootleg  for  a  foot  or  two,  by  two  men  with  double- 
jacks.  When  progress  became  slow,  a  perforated  plate  about  1%  X  6  X 
8  in.  was  slipped  over  the  end  of  the  moil  and  wedged  to  it,  either  with 
two  small  wedges  or  with  one  wedge  and  a  track  spike  as  illustrated.  By 
hitting  the  head  of  the  wedge  with  the  two  doublejacks,  the  moil  was 
extracted.  During  this  process,  it  was  usually  supported  on  a  log  as 
shown,  to  keep  the  plate  off  the  ground. 

The  moil  hole  was  then  blasted  by  inserting  a  stick  or  two  of  powder 
and  exploding  with  an  electric  cap.  These  alternating  processes  were 
continued  until  the  desired  depth  of  hole  was  obtained,  the  average  di- 
ameter being  perhaps  12  in.  This  intermediate  blasting  was  done  with  a 
single  dry  cell.  It  was  somewhat  surprising  at  first  to  see  the  miner  load 
his  hole,  step  a  foot  or  two  to  one  side  of  the  collar,  connect  his  battery, 

58 


ROCK  DRILLS 


59 


and  set  it  off.  As  a  matter  of  fact,  material  was  not  even  shot  out  of 
the  mouth  of  the  hole,  the  sole  effect  being  to  shatter  the  ground  adjacent 
to  the  charge.  To  remove  the  broken  material,  the  long-handled  spoon 
shown  was  used.  It  is  made  of  an  ordinary  No.  2  shovel  by  bending 
the  sides  up  straight  so  as  to  give  a  depth  of  about  2  in.  and  opening 
the  socket  to  take  the  large  2-  or  3-in.  end  of  a  peeled  sapling.  When 
the  hole  was  sufficiently  deep,  a  larger  charge  of  dynamite,  10  to  13 
sticks,  was  exploded  in  a  bottom  to  give  a  good  chamber.  Black  powder 
to  the  extent  of  about  three  kegs  was  charged  into  the  chamber  by  shaking 


LONG    MOIL  WITH   PLATE    AND    WEDGE    FOR 
DRIVING    IT  OUT  OF   HOLE 


LOADING    TROUGH 


TAMPING    BAR 
FIG.    52. TYPICAL  SET  OF  GOPHER-HOLE  TOOLS. 

it  down  the  launder  illustrated.  A  dynamite  primer  was  inserted  in  the 
middle  of  the  powder  charge  and  the  whole  tamped  tight  with  the  tamp- 
ing bar  shown  in  the  illustration.  The  remainder  of  the  hole  was  then 
also  tamped  with  lean  ore.  The  tamping  bar  consists  of  a  round,  tapered 
wooden  head  about  4  in.  in  diameter  at  its  big  end  and  14  in.  long,  with 
the  smaller  end  bored  to  permit  the  insertion  of  a  2-in.  sapling  which  is 
fastened  with  a  wooden  dowel  pin. '  No  nails  are  used,  and  in  the  con- 
struction of  the  trough,  copper  nails  are  considered  advisable.  It  is 
an  obvious  rule  of  safety  not  to  bring  iron  and  rock  into  contact  in  the 
presence  of  black  powder. 


60  DETAILS  OF  PRACTICAL  MINING 

The  holes  were  blasted  in  groups  and  for  this  purpose  the  battery 
was  discarded  and  a  push  machine  used.  It  is  customary  to  move  some 
distance  off  for  this  blasting,  but  if  it  be  well  carried  out,  one  might 
stand  on  top  of  the  blast  without  injury,  since  there  is  rarely  any  dis- 
charge of  material,  the  whole  bank  being  lifted  and  allowed  to  drop,  thus 
effectually  shattering  it. 

Cutting  Mass  Copper. — In  the  Lake  Superior  district  a  great  deal  of 
mechanical  cutting  of  copper  is  done  underground  in  order  to  reduce  the 
larger  masses  of  native  metal  to  sizes  which  will  readily  go  into  the  skips. 
The  process  does  not  differ  essentially  from  that  of  cutting  solid  copper 
in  any  form,  and  as  frozen  masses  of  this  metal  are  of  frequent  unwelcome 
occurrence  in  metallurgical  works,  a  description  of  the  method  will  perhaps 
be  of  interest.  As  used  at  present,  the  method  is  essentially  the  same  as 
that  employed  70  years  and  more  ago,  the  difference  being  that  pneu- 
matic hammers  rather  than  hand  sledges  are  used  to  strike  the  cutting 


FIG.    53. COPPER-CUTTING  TOOL  FOR  PNEUMATIC  HAMMER. 

tool.  The  general  dimensions  and  the  shape  of  this  cutting  tool  are  shown 
in  Fig.  53;  its  length  when  new  may  be  as  much  as  4  ft.,  and  it  is  used 
until  its  length  has  been  reduced  by  continued  sharpening  to  a  few  inches. 
It  is  used  in  a  pneumatic  hammer  of  the  size  and  style  usually  employed 
in  riveting  operations. 

The  operation  of  cutting  a  large  mass  is  as  follows :  After  the  mass 
has  been  freed  from  its  resting  place  in  the  rock,  and  is  lying  loose  on  the 
foot  wall,  it  is  marked  off  by  the  shaft  captain  along  the  lines  which  will 
most  advantageously  divide  it  into  smaller  pieces.  Grooves  are  then 
cut  along  these  lines  by  taking  out  successive  triangular  chips;  when 
cutting  is  being  done  by  a  skilled  operator,  each  chip  is  continuous  through 
the  entire  thickness  of  the  mass.  It  is  much  easier  to  have  the  chips 
thin  out  to  an  edge  on  one  side  than  it  is  to  take  out  a  flat  strip,  the  tool 
being  reversed  at  each  cut.  The  width  of  the  tool  corresponds  closely 
to  that  of  the  cutting  edge  of  the  chisel.  The  hammering  action  serves 
to  compress  the  copper  in  the  chip,  so  that  the  latter  is  about  one-half 
the  length  of  the  groove  from  which  it  came  and  is  correspondingly  large 
in  section.  The  chisels  will  cut  copper  for  a  considerable  time  without 
dulling,  but  they  dull  rapidly  on  the  pieces  of  included  rock  which  are 
frequently  encountered.  The  process  is  slow  and  the  work  tells  on  the 
wrist  and  arms  of  the  operator,  as  the  tool  must  be  held  closely  to  the 


ROCK  DRILLS  61 

copper.  It  is  usual  for  men  to  work  in  pairs,  one  resting  while  the  other 
takes  a  cut  through  the  mass.  Two  men  working  in  this  way  under 
ordinary  conditions  will  probably  cut  1  sq.  ft.  of  area  per  shift,  making 
the  labor  cost  approximately  $6  per  square  foot,  which  is  about  one-half 
of  the  cost  with  the  old  method  when  one  man  held  the  chisel  for  two 
men  striking  alternately. 

The  opinion  has  popularly  existed  in  the  minds  of  many  that  copper 
may  readily  be  cut  by  the  oxyacetylene  process.  Various  inquiries  have 
led  to  the  conclusion  that  this  process  is  entirely  inapplicable,  at  least 
in  a  way  similar  to  that  in  which  it  is  applied  in  cutting  steel.  It  will  be 
remembered  that  the  latter  is  essentially  an  oxidizing  process,  steel 
oxidizing  very  rapidly  in  an  atmosphere  of  oxygen  when  heated  to  the 
temperature  of  the  oxyacetylene  flame.  Copper  does  not  oxidize  readily 
in  this  way,  and  its  high  heat  conductivity  is  also  a  factor  as  preventing 
the  localization  of  the  heat.  It  is  not  known  that  the  method  has  been 
tried  out  locally  on  mass  copper,  but  it  has  been  tried  at  refineries  by 
men  expert  in  its  use  and  these  attempts,  so  far  as  known,  have  resulted 
in  flat  failures. 

Machine-driven  Auger  for  Soft  Ground. — On  the  Lake  Superior  iron 
ranges  it  has  been  customary  to  drill  the  holes  in  certain  soft  ores  with 


FIG.    54. BAR  SECTION  AND  FORMED  BIT. 

hand  augers.  It  is  now  becoming  rather  general  practice  to  use  an  auger 
bit  in  a  hand-held  rotating  hammer  machine.  Soft  ground  has  been 
usually  considered  unsuitable  for  this  type  of  machine,  inasmuch  as  the 
steel  tended  to  bury  itself.  It  is  evident  that  with  an  auger  bit  the 
difficulty  is  avoided,  since  the  action  of  the  twisted  steel  is  that  of  a  screw 
conveyor,  rapidly  clearing  the  hole  of  all  cuttings.  The  rotation  of 
the  machine  has  a  certain  amount  of  drilling  effect,  but  the  speed  of 
drilling  is  greatly  increased  by  the  hammering  of  the  piston  on  the 
steel.  A  further  advantage  lies  in  the  fact  that  when  a  hard  rib  is  en- 
countered, the  regulation  rose-bitted  hollow  steel  can  be  substituted  for 
the  auger  until  the  soft  material  comes  in  again. 

The  success  of  the  machines  is  such  that  they  are  now  made  specially 
designed  for  the  work,  having  a  higher  speed  of  rotation  and  a  lighter 
blow.  The  steel  of  which  the  bits  are  made  is  not  twisted  in  the  shop 
as  in  the  case  of  hand  augers,  but  comes  twisted  from  the  manufacturer. 
The  original  bar  has  a  diamond  cross-section  similar  to  that  shown  in 


62 


DETAILS  OF  PRACTICAL  MINING 


Fig.  54.  It  is  twisted  so  as  to  give  one  complete  turn  per  4  in.  The 
character  of  the  bit  forged  by  the  blacksmith  is  also  shown  approximately. 
The  greatest  diameter  of  the  twisted  bar  is  about  1%  in.  The  bit  of  the 
starter  has  an  overall  diameter  of  2  in.  The  other  pieces  of  the  set 
decrease  about  ^  in-  in  gage  and  increase  about  18  in.  in  length.  The 
shank  end  is  welded  on  in  the  shop;  it  is  hexagonal  and  has  a  small  collar 
to  facilitate  removal  of  the  steel  from  the  hole. 

Removing  Broken  Drill  from  Hole  (By  George  A.  Addy). — An  in- 
genious and  useful  scheme  for  removing  the  bit  end  of  a  broken  drill  steel 
from  a  hole  is  illustrated  in  Fig.  55.  It  consists  simply  of  a  ring  of 
square  iron  A  of  a  suitable  diameter  to  slip  over  the  broken  steel.  Two 
holes  B  are  drilled  on  opposite  sides  of  this  ring  and  a  stout  cord  passed 


FIG.    55. RING  AND  CORDS  FOR  EXTRACTING  BROKEN  BITS. 

through  these  holes  and  knotted  on  the  lower  sides.  The  ring  is  slipped 
over  the  steel  in  a  down-hole,  and  by  loosening  one  cord  and  pulling  on 
the  other,  the  square  corners  of  the  ring  grip  the  steel  so  that  it  may  be 
removed.  In  case  it  is  desired  to  use  the  device  in  a  flat-hole,  one  of  the 
holes  B  is  drilled  large  enough  to  take  the  pointed  end  of  a  scraper,  and 
this  tool  is  used  in  slipping  the  ring  over  the  steel. 


MACHINE  SUPPORTS 

Pneumatic  Drill  Column  (By  Sven  V.  Bergh). — An  important  factor 
to  be  considered  in  getting  the  highest  efficiency  out  of  the  modern 
hammer  drill  is  the  simplification  of  the  drill  mounting  when  such  mount- 
ing is  required.  The  labor  cost,  compared  with  the  other  costs  of  opera- 
tion, is  in  most  cases  predominant,  and  it  must  be  borne  in  mind  that, 


ROCK  DRILLS  63 

roughly  estimated,  only  40  to  50  per  cent,  of  the  total  shift  can  be  used 
for  drilling,  the  rest  being  absorbed  in  setting  up  and  other  manipulation 
of  the  machine.  When  a  column  or  bar  has  to  be  used,  the  drill  may 
be  either  attached  to  it  directly  or  it  may  be  carried  on  an  arm;  the 
column  itself  may  be  of  either  the  single-screw  or  the  double-screw  type. 
In  any  case,  its  height  is  adjustable  to  only  a  limited  extent.  Hence,  to 
make  a  set-up  in  the  best  position  for  the  round  of  holes  to  be  drilled, 
the  workman  has  to  use  a  good  deal  of  skill  and  do  considerable  planning; 
in  most  cases  a  lot  of  time  is  wasted  in  mucking,  arranging  blocking,  pick- 
ing down  back  or  picking  up  bottom,  in  order  to  get  good  bearing  surfaces 
for  the  column. 

To  facilitate  these  operations,  a  pneumatic  drill  column  was  devised 
and  has  been  used  with  good  results  for  several  years  at  the  iron  mines  of 
Malmberget,  Sweden.  It  resembles  in  general  the  telescopic  air-feed  of 
the  stoper  type  of  drill.  A  longitudinal  section  is  shown  in  Fig.  56. 
The  height  of  this  particular  column  can  be  varied  between  6.23  and 

o^'A -_   .--To  suit  inner  tube 
(OK  YF-K^-Same  as  outer  tube     Air  Inlet 
^Stuffing  Box,       ^R  |p 
Inner  tube  2  pipe  J- 


O['j                                                i       ~7      y          l iifi A "  Outer  tube 2 "pipe 
3 "'66'6  U""»"  "-'-••---•"-"-- 66  Si- 


FIG.    56. COMPRESSED-AIR  TELESCOPIC  MOUNTING  FOR  LIGHT  DRILL. 

11.48  ft.  When  the  column  is  fully  run  out,  the  compressed  air  is  shut 
off  by  means  of  an  automatic  cut-off  valve.  There  is  no  need  of  the 
usual  arm  in  order  to  provide  a  sufficiently  wide  range  of  positions  for 
the  machine.  The  column,  drill  and  all  are  easily  removed  from  one 
position  to  another  as  required,  and  the  absence  of  an  arm  makes  this 
all  the  easier.  The  drill  clamp  is  adjustable  with  one  single  screw-bolt, 
and  is  made  with  a  hinge  so  that  the  machine  can  be  swung  over  to  one 
side  when  the  drill  steel  has  to  be  changed.  The  clamp  is  attached 
to  the  outer  tube.  This  has  a  toothed  foot-piece  which  bears  on  the 
bottom  and  resists  rotation.  The  inner  tube  ends  in  a  point  which 
bears  against  the  back.  It  is,  of  course,  not  subject  to  any  torsion. 

The  column  was  found  sufficiently  stable  when  the  regular  drilling 
pressure  was  used,  but  is  adapted  only  to  light  hammer  drills  of  the 
stoper  type  with  telescopic  air-feed  and  for  drilling  in  soft  to  medium- 
hard  rock.  It  should  be  noted  that  when  air  is  turned  off,  the  machine 
first  stops  drilling  and  the  air  in  the  column  maintains  static  pressure 
for  some  time.  It  can,  however,  be  exhausted  rapidly  if  desired. 

Tripod  for  Handling  Long  Drill  Steel  (By  Le  B.  Reifsneider).— A 
device  has  been  found  useful  by  the  Spanish- American  Iron  Co.  for  hand- 
ling long  pieces  of  steel  when  drilling  vertical  holes  up  to  35  ft.  in  depth, 


64  DETAILS  OF  PRACTICAL  MINING 

using  tripod  drills.  It  consists  of  the  parts  of  an  old  tripod  so  badly 
worn  as  to  be  no  longer  safe  as  a  drill  mounting.  The  usual  short 
pipe  legs  are  removed  and  replaced  with  lengths  of  1%-m.  pipe,  the 
latter  being  threaded  and  having  a  coupling  on  the  lower  end  for  con- 
venience in  adding  short  lengths  of  pipe  when  it  is  desired  to  increase 
the  height  of  the  rig.  An  eye-bolt  is  put  into  the  opening  in  the 
saddle  so  as  to  hang  down  and  is  secured  there  by  a  washer  and  nut, 
and  a  single  block  with  a  M~m-  manila  line  rove  through  it  is  hooked 
into  the  eye-bolt.  The  line  is  two  and  a  half  times  the  length  of  the 
tripod  legs,  and  at  one  end  a  simple  straight  hook  of  J£-in.  round  iron  is 
fastened. 

In  use  this  modified  tripod  is  first  laid  out  on  the  ground,  the  front 
legs  are  spread  to  a  width  that  will  make  a  stable  base,  usually  about 
one-half  the  height  although  sometimes  less,  and  all  bolts  are  drawn  up 
and  tightened  except  the  nut  on  the  through  bolt  which  holds  the  rear 
leg.  The  block  is  then  hooked  into  the  eye-bolt,  the  rope  rove  and  the 
tripod  raised  and  moved  over  the  hole  where  the  machine  is  drilling,  so 
that  the  hook  on  the  rope  falls  approximately  over  the  center  of  the  hole. 
In  removing  a  piece  of  steel  from  the  hole  it  is  first  pulled  up  as  far  as  it 
can  be  conveniently  handled  with  the  dolly  bars;  one  man  then  lets  go 
the  dolly  bar  and  takes  three  turns  of  the  hook  end  of  the  rope  around 
the  steel  close  to  the  collar  of  the  hole,  fastening  the  hook  back  over  the 
rope  above  the  turns  on  the  steel.  He  then  pulls  the  rope  taut  and  takes 
several  turns  around  the  rear  leg  of  the  small  tripod  on  which  the  drill  is 
mounted.  As  soon  as  he  has  done  this,  the  other  man  lets  go  the  dolly 
bar  and  aids  the  man  at  the  rope  to  pull  the  steel  up  until  the  bit  swings 
clear  of  the  collar.  After  this  the  steel  is  lowered  by  paying  out  the  turns 
of  the  rope  on  the  leg  of  the  drill  tripod.  The  steel  is  always  handled 
between  the  two  front  legs  of  the  rig,  since  this  gives  greater  stability. 

The  regular  drill  crew  of  two  men  can  raise  a  piece  of  steel  35  ft.  long, 
using  a  tripod  22  ft.  high.  The  rig  is  used  for  all  steel  over  20  ft.  in 
length.  Beside  the  saving  of  time  and  labor  in  handling  the  steel  this 
is  also  a  valuable  safety  device,  since  by  using  the  drill-tripod  leg  as  a 
snubbing  post  the  steel  is  always  under  control  and  can  be  handled 
safely  on  a  narrow  ledge  in  a  high  wind. 

Simple  Machine  Bar. — In  Fig.  57  is  shown  the  design  of  machine 
bar  used  in  the  mines  of  the  lead  district  of  southeastern  Missouri. 
It  is  a  one-screw  post  without  any  header  casting  at  either  end.  The 
teeth  for  gripping  the  top  blocking  are  made  by  cutting  the  pipe 
used  for  the  column  in  two  by  drilling  it  full  of  holes.  The  pipe  is  then 
plugged  with  a  piece  of  oak  to  keep  grit  from  getting  down  into  the 
thread  of  the  jacking  screw.  The  illustration  shows  this  block  only 
partly  driven  in.  A  collar  of  2%  X  %-\TL.  iron  is  shrunk  on  the  upper 


ROCK  DRILLS 


65 


end  to  reinforce  it  after  the  plug  has  been  hammered  in.  A  similar 
collar  is  also  shrunk  on  the  bottom  after  the  jack  screw  has  been  put 
in.  There  is  no  shoe  on  the  bottom  end  of  the  jacking  screw.  It  simply 
ends  in  a  blunt  point.  Formerly  this  was  stuck  in  the  axle  hole  of  a 
car  wheel  in  making  a  set-up,  but  the  ends  often  penetrated  too  far  into 


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FIG.    57. MACHINE  BAR  tfiSED  IN  SOUTHEASTERN  MISSOURI. 

the  wheel  and  as  the  side  strain  was  strong  on  the  jacking  screw  the 
result  was  that  several  screws  would  be  broken  in  the  course  of  a  month. 
On  that  account  simple  plates  about  6  or  8  in,  wide  and  1  in.  thick, 
with  a  depression  in  the  center  for  taking  the  end  of  the  jack  screw,  are 
now  provided.  These  do  not  let  the  jack  screw  enter  far  enough  to 
put  any  side  strain  on  the  screw.  With  this  shoe  plate  it  is  possible  to 


66 


DETAILS  OF  PRACTICAL  MINING 


set  up  without  any  trouble  on  a  steeply  slanting  bottpm.  If  there  were 
a  shoe  to  the  jack  screw,  a  considerable  side  strain  would  be  thrown  on 
the  screw  unless  a  block  was  put  under  it  to  level  up  with  such  a  slop- 
ing bottom  in  order  that  the  column  could  be  stood  perpendicular  to  the 
foot  blocking.  In  other  words,  more  care  has  to  be  taken  in  making 
a  set-up  when  a  foot  shoe  is  used  than  when  one  is  not,  and  since,  there- 
fore, the  work  of  setting  up  with  this  type  of  shoeless  column  is  easier 
and  quicker,  the  machinemen  like  it  better  than  the  bar  of  the  regula- 
tion type.  As  the  column  is  always  set  up  on  solid  rock  in  this  district, 
the  fact  that  the  end  of  the  jack  screw  is  not  of  large  area  is  unimportant. 


FIG.  58. — SHOE  FOR  TRIPOD  LEG  ON  BROKEN  GROUND. 

Steady  Tripod  Set-up  on  Loose  Rock. — In  certain  classes  of  mining, 
especially  with  some  types  of  underhand  stoping,  and  where  the  ore- 
body  is  too  wide  for  a  column,  a  tripod  set-up  for  the  drills  is  frequently 
necessary.  Often  it  is  not  possible  to  place  the  tripod  legs  on  solid 
rock  and  the  yielding  set-up  which  results  interferes  with  good  drilling. 
When  such  a  set-up  is  necessary,  several  expedients  are  employed  to 
steady  the  drill  and  distribute  its  weight  over  a  large  area.  In  some 
Missouri  mines  the  tripod  is  set  on  old  car  wheels,  but  these  are  heavy 
to  handle  and  if  mixed  with  the  ore  might  cause  serious  delays  around 
the  gyratory  crusher.  In  Butte  wooden  blocks  are  employed,  but 
unless  they  are  at  least  5  in.  thick  or  shod  with  iron,  they  are  easily 
split  by  the  sharp  ends  of  the  tripod  leg. 

A  device  used  by  the  Cleveland-Cliffs  Iron  Mining  Co.,  in  Michigan, 
consists  of  a  10  X  12-in.  piece  of  3-in.  oak,  Fig.  58,  shod  with  a  5- 


ROCK  DRILLS  67 

or  6-in.  square  of  %-in.  scrap  iron.  The  shoe,  which  is  fastened  to 
the  block  by  four  J^-in.  carriage  bolts,  has  a  depression  about  1  in. 
in  diameter  and  1J^  in.  deep,  to  receive  the  tripod  leg.  To  prevent 
splitting,  the  block  is  bound  together  at  each  end  by  a  J^-in.  bolt. 

Steadying  Leg  for  Rock-drill  Bars. — In  sinking  the  No.  2  Hancock 
shaft  in  the  Michigan  copper  country,  the  rock  drills  were  mounted  on 
arms  carried  by  a  regular  shaft  bar  with  a  single  screw  at  the  end.  On 
each  arm  a  collar  was  used  carrying  a  leg  to  steady  the  bar  under  the 
hammer  of  the  three  machines  which  were  used  at  one  time,  and  which 
otherwise  would  have  made  it  difficult  to  keep  the  bars  tight.  The  de- 
tails of  this  steadying  leg,  with  the  collar  by  which  it  is  attached  to  the 


Huf  Shrunk  in  Pipe 


Y 

^,  \ 

Old -Feed  screw      Squared  fo/f-fo 
f^^l'mnr^ine    recel ve  machine 
spanner 


Machine  bar  4" 
gaspipe 


FIG.    59. DRILL-ARM  STEADIER  USED  IN  HANCOCK  SHAFT. 

arm,  are  shown  in  Fig.  59.  The  device  consists  simply  of  a  collar  with 
a  pipe  fastened  to  it,  from  the  lower  end  of  which  extends  a  screw  leg 
made  from  an  old  machine  feed-screw.  The  end  of  this  screw  leg  is 
drawn  down  to  a  sharp  point,  which  is  firmly  braced  and  screwed  out, 
from  time  to  time,  so  that  the  machine  is  kept  braced  tight  from  the 
ground  and  cannot  swing.  It  is  usually  the  surging  of  the  machine 
that  loosens  the  bars.  This  device  steadies  the  arms  upon  which  the 
machines  are  directly  mounted,  and  therefore  the  large  shaft  bar  re- 
ceives far  less  jar  and  vibration  than  would  otherwise  be  the  case. 

Wedged    Arm   for  Drill  Columns   (By  R.   A.   Rule). — The  drill- 
column  arm  generally  used  in  underground  drilling  is  clamped  to  the 


68 


DETAILS  OF  PRACTICAL  MINING 


column  by  two  bolts.  In  the  arm  shown  in  Fig.  60  bolts  are  not  used. 
The  arm  is  attached  to  the  drill  column  by  a  clamp  in  which  a  wedge 
and  slotted  key  are  used  instead  of  the  usual  bolts.  The  wedge  fits 
into  a  slot  in  the  key,  and  by  striking  the  wedge  a  smart  blow  with  a 


Cast  Steel 


Hinge  Jo/nt 
FIG.    60. WEDGE  AND  KEY  DRILL-COLUMN  ARM. 

hammer  the  clamp  is  drawn  tightly  about  the  column.  To  loosen  the 
clamp  the  lower  end  of  the  wedge  is  struck  with  a  hammer.  It  requires 
but  one  hand  to  loosen  the  wedge;  hence  the  other  hand  may  be  used 
to  hold  the  arm  when  the  grip  is  released. 


FIG.  61. HINGED  COLLAR  FASTENED  BY  WEDGE. 

Wedged  Drill-column  Collar  (By  R.  A.  Rule).— Fig.  61  illustrates 
a  four-piece  post  collar,  which  dispenses  with  the  use  of  bolts.  The 
pieces  B  and  C  are  hinged  to  the  piece  A  at  E  and  F,  respectively.  The 
piece  C  passes  through  a  hole  in  the  end  of  the  piece  B  and  is  itself 


ROCK  DRILLS 


69 


slotted  to  receive  the  tapered  key  D,  which  working  on  the  piece  B 
forces  it  against  the  post.  The  blow  of  a  hammer  on  the  key  D  thus 
tightens  or  releases  the  clamp.  The  ease  and  rapidity  of  operation  of  a 
hinged-and-keyed  collar,  as  compared  with  the  usual  bolted  collar, 
results  in  an  appreciable  saving  of  time. 

Copper  Range  Drill  Column. — An  unusual  form  of  drill  column  is 
used  in  the  mines  of  the  Copper  Range  company  in  Michigan.  This  post 
has  two  toothed  ends.  It  is  mounted  on  top  of  a  two-screw  jack  which 
is  fitted  with  a  wooden  center  block  into  which  the  teeth  of  the  bottom  of 
the  column  nip  when  the  post  is  set  up,  Fig.  62.  The  column  and  the 


FIG.    62. TWO-SCREW  DRILL  COLUMN  USED  IN  COPPER  RANGE  MINES. 

jack  are  independent  and  thus  the  weight  is  divided.  Moreover,  one  jack 
can  be  made  to  serve  several  different  lengths  of  column.  This  is  a 
decided  advantage  whenever,  as  at  the  Copper  Range  mines,  it  is  neces- 
sary to  have  several  lengths  of  column  owing  to  the  different  heights  of 
the  back  above  the  filling.  The  advantage  of  a  two-screw  jack  is  ob- 
tained without  the  drawback  of  the  great  increase  in  the  weight  when  it  is 
fastened  tightly  to  the  post  part.  The  jack  nuts  are  castings  that  have  a 
projecting  ledge  for  the  wooden  block  to  rest  upon.  Two  bolts  go  through 
the  block  and  hold  the  nut  castings  and  jack  block  together.  This  jack 
block  lasts  about  a  year  before  it  becomes  so  worn  that  it  has  to  be 
replaced.  The  column  itself  is  simply  a  standard  4-in.  gas  pipe  with 
toothed  head-pieces  shrunk  tightly  into  it  at  both  ends.  Because  of  its 


70  DETAILS  OF  PRACTICAL  MINING 

cheapness,  the  men  in  the  stopes  are  given  three  lengths.     Consequently, 
they  do  not  have  to  build  up  much  blocking  when  making  a  set-up. 

MAINTENANCE 

Handling  Drill  Steel  at  the  Quincy  Mine  (By  L.  Hall  Goodwin). — 
The  method  of  handling  drill  steel  at  the  Quincy  mine,  Hancock,  Mich., 
is  different  from  that  usually  employed  at  the  larger  mines  of  the  Lake 
Superior  district,  where  the  problem  is  to  sharpen  the  steel  for  several 
widely  separated  shafts  at  a  centrally  located  shop.  At  the  Copper  Range 
mines  and  the  Calumet  &  Hecla  the  drills  are  kept  loose  and  are  carried  to 
and  from  the  various  shafts  in  steel  boxes,  each  shaft  having  its  special 
box. 

The  main  distinguishing  feature  of  Quincy  practice  is  that  the  pieces 
of  steel  are  kept  in  slings,  each  sling  containing  8  to  10  pieces,  which  are 
assigned  to  a  certain  contract.  Dull  drills  are  put  up  in  slings  at  the 
working  place  underground,  and  sharp  ones  before  they  leave  the  shop. 
The  sling  consists  of  a  piece  of  J^-in.  flat  iron,  1%  in-  wide,  formed  into 
a  ring  having  an  inside  diameter  of  4  in.  The  steel  is  held  in  this  ring 
by  means  of  three  wooden  wedges,  8  in.  long,  placed  side  by  side,  the 
middle  one  being  reversed  end  for  end  with  respect  to  the  other  two,  and 
hammered  into  place;  this  forms  a  firm  bundle  of  convenient  size  for 
handling. 

All  miners  have  a  contract  number,  although  only  those  employed 
in  mine  development  actually  work  on  contract;  for  other  miners,  the 
number  is  used  only  in  distributing  tools  and  supplies.  Each  piece  of 
drill  steel  is  assigned  to  a  certain  contract,  and  the  number  of  that 
contract  is  cut  on  its  shank. 

Dull  steel  is  sent  to  surface  and  sharp  steel  sent  underground  after 
each  shift  has  gone  off.  The  dull  steel  is  carried  to  the  shaft  by  the  miners 
and  dropped  where  it  can  be  loaded  easily  into  the  south  skip,  as  it  has 
become  an  arbitrary  rule  at  this  mine  always  to  use  the  south  skip  for 
handling  tools  and  supplies.  When  all  men  are  up,  the  man-cars  are 
immediately  replaced  by  skips,  and  the  first  skip  hoisted  in  the  south  road 
picks  up  the  slings  of  dull  steel  from  all  the  levels;  the  sharp  drills  are  sent 
down  on  the  next  trip  of  the  same  skip. 

At  surface,  the  skip  automatically  discharges  its  load  of  steel  at  a 
special  dump- just  above  the  collar  of  the  shaft.  It  passes  into  a  concrete 
chute,  the  bottom  of  which  is  faced  with  old  rails,  flange  up.  This 
chute  starts  off  at  30°,  but  its  inclination  gradually  changes  to  horizontal 
and  it  then  forms  a  platform  at  a  convenient  height  for  loading  on  a 
wagon.  The  dull  steel  is  collected  and  the  sharp  distributed  by  one  of 
the  surface  teams.  The  slings  of  sharp  steel  are  stood  up  in  a  row  of 


ROCK  DRILLS 


71 


racks  along  the  south  side  of  the  shafthouse,  the  racks  being  numbered 
to  correspond  to  the  working  levels. 

The  accompanying  illustration,  Fig.  63,  shows  a  plan  of  the  drill 
shop.  It  will  be  largely  self-explanatory  after  it  is  stated  that  the  drills 
are  transported  from  one  part  of  the  shop  to  another  on  flat-topped  cars 
having  rigid  trucks  which  necessitate  straight  tracks  and  turntables. 
An  extension  of  the  track  reaches  four  hand  forges  used  in  shanking  the 

.  COKE  FEEDING  APRON, 


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\ 

LOAD.  SHARP 
DRILL  STEEL 

DR1LL  ST 
SLINGS 
STEEL,  ON 
.'  SHAFT  I 

«] 

ANDS  FOR 
OF  SHARP 
E.  FOR  EACH 

OF  PIGEON—' 
OMPARTMENP 
*>RP  STEEL 

EXT 

_^ 

ENS10N  OF  T 
D  SHANKING 

FORGFS. 

) 

)           U 

T 

STACK 
HOLE  ( 
fOR  SH, 

) 

-JH     T 

FIG.    63. LAYOUT  OF  THE  QUINCY  DRILL-SHARPENING  SHOP. 

steel.  The  drill  sharpeners  used  are  a  modified  form  of  the  Word  machine. 
Drill  stands  consist  of  two  wooden  horses  set  at  a  convenient  distance 
apart,  their  tops  faced  with  a  3-in.  strap  of  J^-in.  iron.  The  tops  of 
the  cars  are  36  X  48  in.,  and  four  iron  stakes  fit  into  tenons  at  each 
corner. 

The  sharp  steel  is  sorted  by  boys  in  front  of  a  stack  of  pigeon-hole 
compartments,  drills  belonging  to  each  contract  being  kept  in  a  separate 


72 


DETAILS  OF  PRACTICAL  MINING 


compartment.  The  pigeon  holes  are  numbered  in  order  by  contracts, 
and  the  shaft  and  level  numbers  are  also  given.  The  sharpened  drills 
are  removed  from  the  pigeon  holes  by  other  boys,  who  bundle  them  into 
slings;  the  slings  going  to  each  shaft  are  segregated  on  one  drill  stand, 
the  shaft  number  being  marked  with  white  chalk  on  the  ring,  the  contract 
number  with  blue  chalk  on  the  wedges.  The  slings  are  left  on  the  drill 
stands  until  a  truck  load  of  them  has  accumulated ;  they  are  then  wheeled 
out  to  the  loading  platform. 

As  compared  with  the  practice  of  the  other  Lake  mines,  the  Quincy 
system  has  the  marked  disadvantage  that  the  drills  are  handled  a  greater 
number  of  times  by  hand  than  is  usual ;  this  disadvantage  is  largely  offset 
by  keeping  the  drills  in  bundles.  The  principal  advantages  of  the  method 


FIG.    64. SHIM  FOR  WORN  MACHINE-DRILL  CLAMPS. 

may  be  stated  as  follows:  All  sorting  is  done  in  the  drill  shop,  where  it 
may  be  easily  supervised;  drills  for  each  contract  are  in  rigid  bundles, 
which  tends  to  secure  better  distribution;  the  drill  steel  is  easily  handled 
while  being  distributed  to  the  underground  working  places;  this  latter 
point  is  of  especial  force  in  minimizing  delays  to  the  hoisting  plant,  which 
is  an  important  factor  at  these  deep,  low-grade  mines. 

Repairing  Worn  Clamp  (By  George  E.  Addy). — When  the  gripping 
portion  of  a  machine-drill  clamp  or  saddle  becomes  worn  large,  or  when 
the  saucer  bases  of  the  machines  are  worn  small,  it  may  be  impossible  to 
bring  the  clamp  jaw  to  bear  on  the  machine  base.  In  such  a  case,  the 
clamp  may  be  continued  in  service  by  using  the  device  illustrated  in 
Fig.  64.  The  flat  ring  is  fastened  to  the  clamp,  so  as  to  act  as  a  shim, 
and  by  slightly  raising  the  base  of  the  machine,  enable  it  to  be  gripped 
by  the  jaw.  In  the  drawing  the  ring  is  shown  as  riveted  by  countersunk 
rivets  through  the  overhanging  edge  of  the  clamp.  If  this  overhang  does 


ROCK  DRILLS 


73 


not  exist,  countersunk  screws  can  be  substituted.  They  are  better> 
except  that  they  require  more  labor  to  put  in. 

Drill  Tester  for  the  Shop. — A  device  for  obtaining  graphically  and 
rapidly  many  of  the  essential  characteristics  of  rock  drills  without  sub- 
jecting them  to  actual  drilling  tests  has  been  devised  by  William  D. 
Paynter,  of  Grass  Valley,  Calif.,  the  machinist  in  charge  of  the  repair 
and  upkeep  of  machine  drills  of  the  North  Star  mine.  Its  general 
appearance  with  a  stoper  under  test  is  shown  in  Fig.  65. 

The  base  has  a  pedestal  bolted  to  its  left-hand  end  in  which  a  vertical 
pillar  is  clamped  by  a  split  collar.  This  pillar  carries  a  horizontal 
longitudinal  arm  on  which  may  be  clamped  an  ordinary  saddle  for  a 
piston  or  Leyner  machine,  or  a  carrier  for  use  as  a  back-stop  with  air- 


0/1 'Reservoir 


ragm  Chamber 

Mu/t/p/y!ng  Lever 

•Pencil 

Iv 

Motor 
frt/mfbrfbper 


a/Chambers 


Pillar 


fbperoa 
Prvm 


Pft/ff/p/y/nq  lever 


FIG.    65a. PLAN    OP    DIA- 

FIQ.    65. ELEVATION  OF  DRILL-TESTING  MACHINE.  PHRAGM,       RECORDING       ARM 

AND  DRUM. 

feed  hammer  stopers.  An  air-feed  stoper  is  shown  suspended  by  hangers 
from  a  suitable  support.  The  pillar  permits  vertical  adjustment  and 
the  clamp  gives  a  horizontal  movement.  The  central  part  of  the  base 
rises  to  carry  the  cylinder  and  plunger  device  as  shown.  One  end  of  the 
plunger  projects  through  the  cylinder  and  against  this  bears  a  bar,  which 
is  substituted  for  the  bit  in  the  drill.  The  other  end  of  the  cylinder 
communicates  with  a  pipe  to  the  diaphragm  chamber,  carried  on  a 
framework  at  the  right-hand  end  of  the  machine. 

The  diaphragm  chamber  is  shown  in  more  detail  in  Fig.  65a.  It 
consists  of  a  plate,  recessed  to  form  a  chamber  which  is  closed  with  a 
diaphragm  of  highly  tempered  steel.  This  diaphragm  is  held  under  a 
cover  ring  and  its  motion  is  adjustable  by  studs  on  the  inside  and  stop 
rings  in  the  nature  of  bushings  on  the  outside.  The  cylinder,  pipe  and 
diaphragm  chamber  are  filled  with  oil  by  a  pump  from  the  reservoir 
shown,  and  there  is  also  connected  with  this  oil  system  a  pressure  gage. 
A  rod  is  secured  to  the  center  of  the  diaphragm  so  as  to  move  with  it,  and 
carries  a  spring  which  governs  its  motion  somewhat.  An  arm  called  the 


74 


DETAILS  OF  PRACTICAL  MINING 


multiplying  lever  is  moved  by  this  diaphragm  rod,  being  pivoted  at  one 
end  and  carrying  a  recording  pencil  on  its  long  arm.  The  pencil  bears 
against  the  paper  on  a  revolving  drum  which  is  driven  through  worm 
gearing  by  a  small  motor. 

The  feed  pressure  and  blows  of  the  drill  are  communicated  to  the 
plunger  by  the  bar  which  bears  against  the  plunger  end.     They  are 


PIG.    66. TYPICAL  CARDS  OBTAINED  WITH  THE  TESTER. 

transmitted  by  the  non-compressible  oil  so  as  to  vibrate  the  diaphragm, 
the  movements  of  which  are  magnified  by  the  pencil  arm  and  recorded 
on  the  paper  of  the  drum.  The  speed,  of  the  drum  is  uniform  and  can 
be  calibrated  by  the  use  of  a  pendulum.  The  movement  of  the  pencil 
across  the  paper,  corresponding  to  the  strength  of  the  blows,  can  be 
calibrated  by  measuring  it  against  readings  on  the  pressure  gage. 

The  method  of  testing  is  somewhat  as  follows:    The  drum  with  the 
paper  on  its  periphery  is  revolved  with  no  pressure  on  the  diaphragm, 


ROCK  DRILLS  75 

the  line  A,  Fig.  66,  is  thus  obtained.  It  is  then  revolved  in  the  case  of  a 
stoper  with  the  air  pressure  on  the  telescope  feed,  but  with  the  hammer 
not  moving,  giving  the  line  P.  The  drill  is  then  allowed  to  reciprocate 
and  its  blows  give  the  irregular  line  shown,  the  impact  of  the  hammer 
forming  the  line  BC  and  the  return  of  the  diaphragm,  the  line  CD. 

The  upper  card  in  Fig.  66  represents  a  test  on  a  typical  stoper  in  which 
the  air  pressure  was  100  lb.,  the  number  of  blows  struck  was  1284  per 
minute,  and  the  foot-pounds  developed  per  blow  calculated  to  be  50. 
This  would  show  a  little  less  than  2  hp.  developed.  In  the  middle  card, 
obtained  from  a  similar  machine,  there  will  be  noted  a  secondary  blow, 
the  cause  and  effect  of  which  are  not  yet  determined.  In  this  case  the 
air  pressure  was  96  lb.,  the  blows  per  minute  1260  and  the  foot-pounds 
per  blow,  40.  The  lower  card  was  obtained  from  a  machine  in  poor 
shape.  The  air  pressure  in  this  case  was  84  lb.,  the  blows  per  minute 
1272,  and  the  foot-pounds  per  blow,  probably  about  15.  These  last  two 
mentioned  machines  drilling  in  hard  rock  under  the  same  pressure,  84 
lb.,  made  0.105  ft.  and  0.051  ft.  per  minute,  respectively,  thus  confirming 
the  indications  of  the  tester.  It  is  evident  that  the  tester  fulfills  much 
the  same  function  as  a  steam-engine  indicator  in  giving  an  energy 
graph,  valuable,  however,  more  for  its  indications  of  condition  and 
adjustment  than  for  the  quantitative  measurements.  It  differs  from 
the  steam-engine  indicator  in  measuring  output  rather  than  input. 

The  development  of  the  machine  grew  out  of  the  necessity  of  pre- 
venting defective  drills  from  going  underground.  At  the  North  Star 
the  machines  are  usually  taken  on  a  truck  from  the  shop  to  the  shaft 
collar,  unloaded,  and  loaded  on  a  cage,  unloaded  again  at  the  shaft  turn-, 
loaded  on  a  truck  to  go  up  the  main  raise,  unloaded  at  a  level  station, 
loaded  in  a  car  and  taken  to  the  top  or  bottom  of  a  stope,  unloaded  and 
carried  to  the  working  face.  Evidently  this  is  a  process  costing  money. 
If  the  machine  will  not  drill  when  set  up,  it  means  a  definite  loss  to  the 
company,  augmented  by  the  fact  that  the  irritated  miner  will  work  less 
efficiently  for  the  rest  of  the  shift.  It  was  found  impossible  to  detect 
the  defective  machines  in  the  shop.  One  which  might  sound  all  right 
and  work  well  when  set  up  and  run  against  a  block  would  prove  quite 
useless  underground.  To  get  a  more  definite  line  on  the  conditions  of 
the  drills,  a  simple  machine,  embodying  the  principle  described,  was 
built  and  this  more  complete  and  convenient  device  was  developed 
therefrom. 

The  tester  has  served  this  purpose  excellently,  but  it  also  lends  itself 
to  investigation  along  other  lines.  The  effects  of  changes  in  pressure, 
lubricant,  etc.,  can  all  be  investigated  in  this  way  more  easily  and  more 
exactly  than  by  actual  drilling  tests.  A  test  to  ascertain  the  effect  of  a 
difference  in  pressures  indicated  that  a  drop  of  32  per  cent,  caused  a 


76  DETAILS  OF  PRACTICAL  MINING 

drop  in  the  strength  of  the  blow  of  31  per  cent.,  but  a  drop  in  speed  of 
only  12  per  cent.  Underground  tests  showed  that  a  drop  in  air  pressure 
of  28  per  cent,  gave  a  decrease  in  drilling  speed  of  47  per  cent,  with  sharp 
steel;  a  pressure  drop  of  22  per  cent,  gave  a  drilling-speed  decrease  of 
46  per  cent,  with  dull  steel;  a  pressure  drop  of  28  per  cent,  in  another 
case  gave  a  drilling-speed  drop  of  only  25  per  cent. 

A  test  with  different  lubricants  showed  that  a  change  from  heavy 
lubricant  to  medium  gave  an  increase  in  blows  per  minute  from  1116  to 
1212  and  of  foot-pounds  per  blow  from  25  to  34,  while  a  change  to  light 
oil  again  gave  increases  to  1224  and  38.  This  test,  however,  was  made 
on  a  new  machine  and  it  may  be  that  smaller  differences  would  be  found 
in  the  case  of  an  old  machine. 

The  statement  is  frequently  made  that  excessive  air  consumption 
indicates  that  a  drill  is  in  bad  condition.  A  large  number  of  tests 
indicated  that  machines  of  a  certain  type  had  an  average  air  consumption 
of  75  to  80  cu.  ft.  of  free  air  per  minute  at  90  Ib.  pressure.  A  test  of 
a  machine  of  this  type  using  90  cu.  ft.  gave  1296  blows  and  43  ft.-lb., 
high  figures,  which  indicate  that  increased  air  consumption  does  not 
necessarily  indicate  poor  condition.  A  further  field  of  usefulness  lies 
in  testing  out  new  equipment.  Thus  in  one  instance  four  new  valves 
were  obtained  from  the  manufacturers  and  when  tested  in  machines, 
one  was  found  defective.  Investigation  showed  a  piece  of  steel-cutting 
clogging  a  port  so  as  to  throttle  the  air  and  reduce  the  strength  of  the 
blow  35  per  cent. 

It  would  seem  as  if  one  of  the  most  extensive  fields  of  application 
of  the  device  would  be  in  comparing  drills  of  different  makes.  Many 
inferior  types  could  be  eliminated  at  once  in  a  preliminary  test  on  the 
machine  and  only  the  high-class  drills  reserved  for  further  test  in  rock. 

Failure  and  Heat  Treatment  of  Drill  Steel  (By  Sven  V.  Bergh).— 
The  steel  generally  used  for  rock  drilling  may  be  classified  as  carbon  steel; 
hence  the  degree  of  hardness  means  the  percentage  of  carbon  contained. 
Experience  has  proved  that  the  proper  percentage  of  carbon  is  governed 
chiefly  by  the  hardness  of  the  rock  to  be  drilled  and  by  the  power  of  the 
machine.  The  harder  the  rock,  the  softer  must  be  the  steel.  This  is 
due  to  the  fact  that  the  bit  will  not  stand  the  impact  if  too  hard  a  steel 
is  used  to  penetrate  hard  ground,  the  degree  of  hardening  necessary  to 
improve  the  wearing  qualities  of  the  bit  depending  upon  the  conditions 
under  which  it  has  to  be  used.  The  above  rule  must  also  be  applied 
when  a  heavier  type  of  drill  is  being  substituted  for  a  lighter  one  and  the 
steel  does  not  seem  to  stand  up  well.  The  ultimate  carbon  hardness  being 
already  reached,  a  softer  steel  must  be  tried. 

In  some  drilling  practice,  as,  for  instance,  when  hand-feed  drills  are 
used,  bending  stresses  are  likely  to  be  put  on  the  steel.  Additional 


ROCK  DRILLS 


77 


tensile  and  compressive  stresses  are  thus  induced  during  the  period  of 
the  blow,  producing  an  excessive  strain  in  the  steel.  In  such  practice  a 
heavy  size  of  steel  is  to  be  recommended.  When  the  steel  is  shanked  it 
is  of  importance  to  give  the  shank  sufficient  length  and  cross-sectional 
area.  It  happens  not  infrequently,  where  a  light  type  of  drill  has  been 
substituted  for  a  heavier  one,  that  the  old  steel  is  continued  in  use.  This 
is  not  advisable,  for  the  additional  reason  that  it  necessitates  a  consider- 


L_^-a^^ 


FIG.    67. SHANK  WITH 

WATER  HOLE. 


Crystalline^ 


FIG.  68.— 
RUPTURE  OF 
SHANK  AND  BIT. 


FIG.    70. — CRACK  DE- 
VELOPING. 


Hardening  Crack  /"~^\ 


FIG.  69. LONGITUDINAL  RUPTURE  OF  SHANKS. 

able  change  in  the  front  head  of  the  machine.  The  number  of  ruptures 
may  sometimes  be  greatly  reduced  by  giving. the  shank  a  greater  cross- 
sectional  area.  In  1911,  tests  were  carried  out  at  a  mine  in  Sweden  to 
find  the  effect  of  such  a  change.  The  rock  at  this  particular  mine  is 
exceedingly  hard  to  drill,  as  it  consists  of  quartz-striped  magnetite  and 
hematite  ore  with  leptite  as  a  country  rock.  During  a  three-month  per- 
iod one  and  the  same  type  of  drill  was  used.  The  following  results  were 
obtained:  Ordinary  shanks  ruptured,  185,  corresponding  to  6277  m. 
drilled;  strengthened  shanks  ruptured,  four  (171  used  in  all),  correspond- 
ing to  700  m.  drilled.  These  figures  show  a  considerable  improvement 


78  DETAILS  OF  PRACTICAL  MINING 

following  the  use  of  the  heavier  shanks.  Here  it  may  also  be  mentioned 
that  all  abrupt  changes  in  section  and  sharp  corners  should  be  strictly 
avoided. 

So  far  as  water-using  drills  are  concerned,  when  the  water  is  fed  into 
the  steel  through  a  radial  boring  it  has  proved  an  advantage  to  drill  the 
hole  at  an  angle  of  45°  with  the  center  hole  of  the  steel,  Fig.  67.  To 
shape  the  shank  and  the  bit,  the  steel  has  to  be  upset  at  both  ends.  This 
operation  changes  the  internal  structure  of  the  steel  unfavorably,  at  the 
same  time  producing  in  some  parts  of  it  the  bad  effect  of  "cold  work," 
due  to  the  manner  of  applying  the  heat.  Ruptures  as  shown  in  Fig.  68 
are  frequently  seen.  Thus  to  utilize  the  best  properties  of  the  steel  it  is 
necessary  that  the  upsetting  be  performed  in  such  a  way  that  the  steel 
receives  the  proper  heat  treatment.  From  this  it  may  be  understood 
why  it  is  regarded  good  practice  to  forge  and  harden  the  bit  in  separate 
heats.  To  obtain  the  finest  grain,  the  bit  has  to  be  forged  continuously 
from  the  highest  temperature  employed  down  to  the  finishing  temperature, 
which  probably  is  slightly  above  the  point  of  recalescence.  It  is  advan- 
tageous in  hardening  not  to  treat  it  to  any  higher  temperature  than  neces- 
sary. The  steel  is  liable,  if  heated  too  high,  to  change  into  a  coarse 
crystallization  and  develop  hardening  cracks  that  may  cause  ruptures. 
The  shank  must  always  be  tempered  properly  after  being  hardened. 

Finally,  it  may  be  mentioned  that  shanks  sometimes  rupture  longi- 
tudinally, Fig.  69.  Some  cases  that  were  investigated  showed  that  the 
failure  was  due  to  careless  straightening  after  the  steel  had  been  upset. 
The  center  hole  of  the  shank  was  thus  oval  instead  of  round  and  this 
later  caused  it  to  rupture  when  the  steel  was  used. 

Two  kinds  of  rupture  may  be  distinguished,  namely:  (1)  Ruptures 
that  appear  as  developed  from  a  coarse-grained  structure;  (2)  ruptures 
that  evidently  have  developed  from  a  partial  break  or  inclosure  in  the  steel. 
In  regard  to  ruptures  of  the  first  class  mentioned,  the  opinion  frequently 
heard  among  users  of  drill  steel  is  that  the  crystalline  texture  often  found 
is  due  to  vibrations.  It  is  not  the  intention  here  to  discuss  whether  such 
an  opinion  is  wrong  or  not,  but  to  call  attention  to  the  fact  that  the  crys- 
talline texture  might  have  been  caused  during  the  manufacture  of  the 
steel  bars  by  wrong  or  insufficient  heat  treatment.  The  crystallized  steel 
is  sometimes  hard  to  restore  completely.  By  annealing,  the  crystals 
may  only  be  more  or  less  broken  up,  still  maintaining  their  previous  orien- 
tation. Thus  cleavage  planes  are  developed  along  which  ruptures  occur, 
giving  the  appearance  of  a  crystalline  fracture,  although  the  steel  in 
reality  is  fine-grained. 

The  typical  fracture  of  the  second  class  is  as  follows:  A  circular  or 
oblong  cavity  or  a  crack  is  found  at  some  part  of  a  transverse  section. 
This  cavity  or  crack  is  surrounded  by  concentric  rings  covering  a  certain 


ROCK  DRILLS  79 

portion  of  the  section,  the  rest  being  more  or  less  covered  by  an  ordinary 
crystalline  fracture,  Fig.  70.  It  has  been  stated  that  these  inclosures 
seemed  to  run  through  the  whole  length  of  the  steel  and  if  it  was  broken 
anywhere,  one  could  expect  to  find  them.  It  is  a  fact  that  this  kind  of 
rupture  occurs  rather  often.  It  is  of  practical  importance  to  determine 
whether  the  inclosures  mentioned  consist  of  slag  or  of  sulphide  of  man- 
ganese, the  latter  usually  occurring  in  the  form  of  round  drops,  which, 
if  large  in  size,  may  be  elongated  by  the  rolling.  Sulphide  of  manganese 
is  best  recognized  by  etching  the  surface  of  the  fracture  with  a  mixture  of 
dilute  hydrochloric  acid  and  bichloride  of  mercury,  when  the  sulphur 
appears  as  dark  spots.  A  print  may  also  be  taken  conveniently  by 
exposing  the  fracture  for  4  or  5  min.  to  a  piece  of  silk  wet  with  the 
solution. 

It  may  be  of  interest  to  many  to  hear  that  ruptures  have  also  been 
found  to  start  from  groove  marks  on  the  steel,  where  numerals  or  other 
marks  have  been  stamped.  It  is  evident  from  what  is  now  said  that  the 
annealing  of  the  drill  steel  at  intervals  will  mean  only  a  partial  improve- 
ment. Internal  strains  produced  by  cold  working  of  the  metal  and  coarse- 
grained crystals  may  be  effaced,  but  there  is  no  possibility  of  eliminating 
ruptures  of  the  second  class  noted.  This  is  in  accord  with  what  has  been 
found  at  various  Swedish  mining  fields  where  the  practice  is  to  anneal 
drills  every  second  month.  The  structure  of  steel  exposed  to  vibrations 
has  proved  to  be  of  utmost  importance.  The  sorbitic  structure  has  been 
found  to  stand  up  best.  It  is  obtained  either  by  cooling  the  steel  quickly 
through  the  go-called  critical  range  without  actual  quenching  or  by  rapid 
cooling  and  then  reheating  to  about  600°  C. 


IV 
SHAFTS  AND  RAISES 

Sinking  and  Timbering — Concrete  Shaft  Lining — Concrete  Skip  Stringers 
— Stations — Raising — Ladders 

SINKING  AND  TIMBERING 

Shaft  Timbering  in  Minnesota  Iron  Mines  (By  L.  D.  Davenport).— 
In  Fig.  71  is  shown  the  timbering  for  a  shaft,  6  X  18  ft.  inside,  sunk 
through  surface,  sand  and  ore  in  the  Chisholm  district  of  Minnesota. 
No  water  was  encountered  until  the  ore  was  reached  and  then  only  a  small 
quantity.  After  the  shaft  was  staked  out,  two  level  trenches  were 
dug  on  the  surface  and  two  bearing  pieces  or  carriers,  40  or  50  ft.  long 
(2-  or  5-ft.  flattened  timber),  were  placed  in  them  about  10  ft.  apart. 
These  40-ft.  bearing  pieces  were  parallel  to  the  wall  plates  and  when  they 
were  leveled  up,  two  cross-carriers  12  X  12  in.  by  20  ft.  were  placed  at 
right  angles  across  them  18  ft.  apart.  The  first  set  was  then  put  in  place 
with  the  end  pieces,  12  X  12  in.  by  8  ft.,  resting  on  the  cross-carriers. 

The  next  set  was  then  put  in  place  below  the  carriers  and  the  stud  dies 
of  this  set  fitted  into  J^-in.  joggles,  cut  in  the  cross-carriers.  These 
studdles  were  cut  off  on  account  of  the  cross-carriers,  so  that  the  distance 
between  the  sets  was  3  ft.  11  in.  The  12  X  12-in.  studdles  in  the  regular 
sets  were  4  ft.  long. 

The  first  set  below  the  carriers  was  like  the  other  sets ;  it  was  held  by 
four  hanging  bolts  of  IJ^-in.  round  iron.  Next,  the  set  which  forms  the 
collar  was  placed  above  the  set  resting  on  the  carriers,  and  diagonally 
braced  to  both  sets  of  bearers.  Four  straight  hanging  bolts  were  used 
here  instead  of  the  hooked  bolts  used  in  the  other  sets.  The  bolts  for 
this  collar  set  were  made  1  ft.  longer  than  the  regular  6  ft.  8  in.  length, 
on  account  of  their  passing  through  the  cross-carriers  as  well  as  the  end 
plates.  As  the  dirt  was  hoisted  it  was  banked  around  the  shaft  collar, 
and  served  not  only  to  steady  the  timber,  but  also  to  keep  out  the  surface 
drainage. 

The  middle  compartment,  used  for  hoisting,  was  boarded  up  as  fast 
as  the  dividers  were  put  in,  so  that  the  bucket  would  not  catch.  The 
dividers  were  put  in  as  the  shaft  was  sunk,  but  the  last  two  sets  were 
always  left  open  to  allow  the  wall  plates  of  the  next  set  to  be  handled. 

80 


SHAFTS  AND  RAISES 


81 


When  the  end  plates  and  wall  plates  were  framed,  a  strip  2X2  in. 
was  spiked  on  the  outside  of  each  piece  in  the  center,  to  make  a  bearing 
for  the  lagging.  The  lagging  was  2-in.  plank  about  4  ft.  9  in.  long. 
Four  hanging  bolts  to  each  set  were  usually  enough,  but  in  heavy  ground 
one  or  two  more  were  sometimes  used  in  the  wall  plates.  Divider 
studdles  or  center  studdles,  6  X  12  in.  by  3  ft.  11  in.,  were  put  in  after 

End Piece 


FIG.    71. DETAILS  OP  SHAFT  TIMBERING  IN  THE  CHISHOLM  IRON  MINES. 

the  dividers,  and  since  these  studdles  were  not  gained  in  to  the  wall 
plates,  small  cleats  were  used  to  hold  them  in  place. 

The  second  set  of  carriers  were  12  X  12-in.  timber  16  ft.  long,  and 
to  put  them  in  place,  small  drifts,  about  3  X  4  ft.,  were  run  in  for  ap- 
proximately 8  ft.  at  the  end  of  the  end  plates  at  two  diagonally  opposite 
corners  of  the  shaft.  Smaller  drifts  were  run  in  about  4  ft.  at  the  other 
two  corners.  The  inside  corners  of  the  8-ft.  drifts  were  rounded  off,  the 
bottoms  trued  up,  and  short  pieces  of  plank  laid  crossways  in  them.  A 
bearer  was  then  brought  down  and  one  end  run  into  the  8-ft.  drift. 


82  DETAILS  OF  PRACTICAL  MINING 

Next  it  was  swung  parallel  to  the  end  plate  and  the  other  end  run  back 
into  the  4-ft.  drift.  The  same  thing  was  done  with  the  other  bearer  and 
the  two  rested  on  the  bottom  boards  of  the  drifts,  directly  under  the 
corresponding  end  plates.  Long,  flat  wedges  were  then  driven  under  the 
bearers  on  top  of  the  boards  and  as  they  were  raised  against  the  end 
pieces,  the  hanging  bolts  were  tightened  to  take  up  the  weight.  When  the 
bearers  were  up  tight  against  the  set  and  well  wedged,  the  small  drifts 
were  carefully  blocked  up  and  the  lagging  put  in. 

Cage  and  Bucket  for  Sinking  (By  Claude  T.  Rice).— The  No.  2 
vertical  shaft  of  the  Hancock  Consolidated  Mining  Co.,  in  'the  Lake 
Superior  copper  region,  was  sunk  to  intersect  the  Pewabic  amygdaloid 
at  a  depth  of  3500  ft.  Although  primarily  an  exploration  shaft,  the 
dimensions,  9J^  X  29^2  ft-,  are  those  of  a  working  shaft.  It  is  the  second 
largest  shaft  in  the  copper  country,  with  four  hoisting  compartments, 
each  7  ft.  long  by  5  ft.  2  in.  wide,  and  one  4  X  7-ft.  ladder-  and  pipe-way. 

The  ground  excavated  in  sinking  to  a  depth  of  2600  ft.  was  raised  to 
the  surface  in  buckets.  Then  a  change  was  made  and  at  the  34th  level 
a  station  was  cut  and  bins  built.  The  material  was  thereafter  raised  in 
buckets  from  the  bottom  of  the  shaft  to  the  bins  and  thence  was  dis- 
charged into  large  skips  in  which  it  was  raised  to  the  surface.  A  rock 
pentice  was  left  below  the  skip  compartments  and  to  prevent  anything 
falling  down  the  shaft  upon  the  miners'  platform,  covers  were  used  over 
the  compartments  in  which  the  buckets  ran,  both  at  the  34th  level  and, 
during  the  first  stage  of  the  sinking,  at  the  surface. 

The  bucket  was  hung  from  a  cage,  instead  of  a  crosshead,  as  shown  in 
Fig.  72.  Two  chains  were  fastened  to  the  clevis  of  the  hoisting-rope 
socket,  and  on  the  end  of  each  a  pair  of  sister  hooks  were  fastened,  which 
hooked  into  ears  on  the  bucket.  At  first  the  hooks  were  fastened  to- 
gether by  a  pin,  scissors-fashion,  but  were  later  used  as  satisfactorily 
without  it.  A  cradle-car  was  used  for  handling  the  backet  on  the  surface. 
On  the  bottom  of  the  bucket  were  two  lugs,  placed  so  that  the  pin,  which 
was  put  through  the  lugs  in  attaching  the  bucket  to  the  cradle  when 
dumping,  would  be  parallel  to  the  line  of  the  eyes  of  the  bucket  ears. 

In  the  bottom  of  the  cage  a  hole  3  ft.  7  in.  in  diameter  was  cut,  the 
diameter  of  the  bucket  at  the  top  being  3  ft.  2  in.  A  flanged  ring  held 
the  bucket  in  position  while  being  hoisted.  There  was  room  between 
the  bucket  and  the  rim  of  the  hole  to  permit  the  heel  of  a  man's  shoe  to 
pass  up  through  as  he  rode  the  bucket  from  the  shaft  bottom  up  to  the 
cage  at  the  beginning  of  a  hoisting  trip,  the  cage  hanging  in  the  shaft 
on  bumpers  fastened  to  the  guides  at  the  bottom  set  of  timbers.  The 
hoisting  rope  passed  freely  through  a  hole  in  the  center  of  the  top  piece 
of  the  cage,  which  was  made  without  a  hood  in  order  to  facilitate  the 
lowering  of  timbers. 


SHAFTS  AND  RAISES 


83 


The  shock  of  picking  up  the  cage  was  absorbed  by  a  rubber  buffer 
on  the  hoisting  rope,  the  buffer  being  about  9  in.  in  diameter  and  6  in. 
thick  and  carried  on  an  iron  plate  of  the  same  diameter  and  %  in.  thick, 
which  rested  directly  on  the  top  face  of  the  rope  socket.  The  bucket, 
when  in  the  cage,  hung  about  5  in.  below  the  deck,  but  entered  the  flange 
far  enough  to  be  steadied.  Friction  between  a  maple  filler  in  the  top 
piece  of  the  cage  and  the  rubber  buffer,  prevented  spinning.  The  deck 
of  the  cage  made  a  fairly  tight  cover  over  the  hoisting  compartment 
when  the  cage  rested  on  the  bumpers  at  the  bottom  set  of  timbers. 


FIG.    72. DETAILS  OF  HANCOCK  BUCKET  CAGE  AND  LANDING  CAR. 

At  the  surface  each  bucket  compartment  was  covered  by  a  platform 
that  traveled  along  the  guides.  As  the  cage  dropped  below  the  collar  of 
the  shaft,  the  corresponding  compartment  was  tightly  covered.  The 
cross-timbers  of  the  platform  extended  out  so  as  to  catch  on  the  top  set 
of  timbers  at  the  collar  of  the  shaft.  Extending  down  from  the  frame 
proper  of  the  cover  were  two  timbers  and  the  top  piece  of  the  cage,  as  it 
came  up,  struck  these  and  carried  the  cover  up  the  headframe  ahead  of  it. 

When  the  bucket  was  detached  from  the  hoisting  cable,  the  shaft 
compartment  was  covered  by  a  sliding  platform  or  landing  carriage  that 
was  pushed  by  compressed  air  across  the  compartment  through  grooves 
in  the  guides.  On  this  carriage  were  tracks  for  the  cradle-car.  In  each 
bucket  compartment  and  at  some  distance  above  the  collar  of  the  shaft 


84 


DETAILS  OF  PRACTICAL  MINING 


was  a  gate  timber  that  could  be  pulled  under  the  cage  as  a  chair  to  hold 
the  cage  while  the  bucket  was  being  lowered  to  the  cradle  car  on  the  land- 
ing carriage.  The  gate  timber  was  fastened  to  a  counterweight  so  that, 
as  soon  as  the  cage  was  lifted,  it  would  move  out  of  the  way  of  the  cage. 
In  making  the  change  of  buckets  at  the  surface  the  car  that  carried 
the  last  bucket  sent  down  on  that  side  would  be  left  standing  in  such 
position  on  the  landing  carriage  that  when  the  carriage  was  moved  into 
the  shaft  the  car  would  come  directly  under  the  bucket  ready  to  receive 
it.  On  the  other  side  of  the  shaft  was  standing  the  car  with  the  bucket 
in  its  cradle  that  had  just  been  dumped.  As  soon  as  the  cage  was 
resting  on  the  gate  timber,  the  landing  carriage  was  run  in  and  the  loaded 
bucket  landed  in  the  empty  cradle.  This  car  was  given  a  push  to  the 
end  of  the  carriage,  the  car  with  the  empty  bucket  was  run  on  and  that 
bucket  attached  to  the  rope.  Then,  as  soon  as  the  bucket  was  raised 


FIG.    73. BUCKET-LANDING  CARRIAGE  USED  AT  TRANSFER  STATION. 


out  of  the  cradle  and  had  picked  up  the  cage,  the  carriage  was  moved  out 
of  the  way. 

At  the  34th  level  the  buckets  were  attached  and  detached  from  the 
cable  on  the  same  side  of  the  shaft.  Fig.  73  shows  the  landing  carriage 
used.  This  carriage  was  moved  in  and  out  of  the  shaft  by  an  air  cylinder. 
The  carriage  was  thrown  in  so  that  the  shaft  would  be  completely  covered 
while  the  bucket  was  being  landed,  and  a  cradle-car  was  run  in  under  the 
bucket.  In  order  to  allow  the  carriage  completely  to  cover  the  shaft 
compartment  the  guides  were  cut  in  two  at  the  station  and  a  3-in.  slot  was 
left  for  the  frame  planks  to  slide  through  as  the  carriage  moved  across  the 
shaft;  thus  no  opening  was  left  around  the  shaft  at  any  time. 

Having  seen  the  moving  of  the  bell  cord  as  the  men  in  the  shaft  signaled 
to  the  hoisting  engineer  to  take  the  bucket  up,  the  three  landers,  on  the 
34th  level,  would  open  the  doors  of  the  compartment  and  get  ready  to 


SHAFTS  AND  RAISES  85 

land  the  bucket.  When  the  cage  had  cleared  the  top  of  the  station,  a 
gate  timber,  similar  to  the  one  used  at  the  surface,  was  pulled  in  across 
the  shaft  so  as  to  catch  the  cage.  After  the  bucket  had  been  landed  in 
the  cradle,  at  the  same  time  being  turned  so  that  the  ears  would  be  inline 
with  the  long  axis  of  the  car  and  out  of  the  way  when  dumping,  the  sister 
hooks  used  to  fasten  the  bucket  to  the  hoisting  rope  were  taken  off,  and 
the  bucket  was  trammed  over  to  the  bin  pockets  by  way  of  a  turntable 
which  was  brought  in  line  with  the  station  track  as  soon  as  the  landing 
carriage  was  moved  into  position  in  the  shaft.  While  the  bucket  was 
being  trammed  to  the  bin,  one  of  the  three  landers  would  stick  a  short 
piece  of  round  iron  through  the  lugs  on  the  bottom  of  the  bucket;  this 
rod  was  long  enough  to  extend  past  the  straps  forming  the  bottom  of  the 


FIG.  74. BLASTING  IRONS  USED  IN  HANCOCK  SHAFT. 

cradle;  thus  the  bucket  was  securely  held  in  the  cradle  while  being 
dumped. 

Kimberley  skips  were  used  to  take  the  muck  from  the  34th  level  to 
the  surface.  These  had  a  capacity  of  8  tons  and  weighed  about  5  tons 
empty.  The  maximum  hoisting  speed  was  3500  ft.  per  minute  with  a 
total  load  of  20  tons,  including  the  rope.  The  speed  of  hoisting  with  the 
bucket  below  the  34th  level  was  2500  ft.  per  minute. 

Blasting  Irons  for  Shaft  Sets. — In  sinking  the  No.  2  Hancock  shaft 
no  cover  platform  was  used  for  storing  the  machine  drills  and  protecting 
the  lower  set  of  timbers  from  flying  rocks  at  blasting  time.  All  the  drill- 
ing equipment  was  raised  to  the  34th-level  station  at  blasting  time. 
Blasting  irons,  the  details  of  which  are  shown  in  Fig.  74,  were  used  to  pro- 
tect the  bottom  timbers  from  being  cut  by  flying  rock.  These  were 
made  of  J^-in.  iron  plates,  punched  with  j^-in.  holes,  so  that  they  could 
be  fastened  to  the  timbers  with  railroad  spikes.  Set  A  was  for  the  wall 
plate  in  the  man  way  compartment,  being  cut  away  for  the  hanging  bolts  on 


86 


DETAILS  OF  PRACTICAL  MINING 


the  under  side.  One  piece  of  the  manway  iron  went  under  the  wall  plate 
and  half  way  up  the  side,  while  to  cover  the  other  half  of  the  inside  space 
a  separate  piece  was  spiked  on.  All  the  other  irons  for  the  wall  plates 
were  similarly  designed,  but  two  other  sets  were  needed,  one  pattern  for 
the  two  compartments  in  which  there  were  no  hanger  bolts,  and  the  other 
for  the  two  compartments  in  which  the  hanger  bolts  were  used.  The 
blasting  irons  for  the  end  plates  were  similar  to  those  for  the  wall  plates, 
except  that  they  were  cut  away  on  the  under  side  to  straddle  the  guides 
and  studdles.  The  irons  for  the  dividers  were  made  in  halves,  each  of 
which  covered  one  side  and  half  the  top  and  bottom.  The  halves  were 
put  on  the  timbers  and  then  held  together  by  two  clamps,  also  cut  away 
to  straddle  the  guides  and  studdles.  The  divider  blasting  irons  could 


IsIeRoyaleTop^SheaveBIochand  Puffer 


Trolley  for  Cable  as  Used  ot 


Endof 


C.ampforrastenj^toTopE 

FIG.    75.  -  TROLLEYS   USED   IN   SINKING   INCLINE   SHAFTS   IN   LAKE    SUPERIOR    COPPER 

COUNTRY. 

be  fastened  on  by  spikes  like  the  others.  Spiking  was  preferred  for 
the  irons  on  the  end  and  wall  plates,  owing  to  the  blocking,  and  because 
when  the  ground  was  bad  they  could  not  conveniently  be  attached  by 
clamps.  The  several  patterns  and  their  place  on  the  set  are  shown  in 
the  illustration. 

Trolleys  for  Sinking  Incline  Shafts.  —  Buckets  are  used  -in  sinking 
incline  shafts  at  the  Lake  Superior  copper  mines.  These  are  carried  by 
a  trolley  that  runs  either  on  a  wire  rope  or  on  an  8-in*.  I-beam  suspended 
from  the  roof  by  chains,  as  shown  in  Fig.  75.  In  order  to  keep  the  I-beam 
from  swinging  upward  with  the  pull  as  the  bucket  is  being  loaded,  it  is 
usual  to  hang  the  top  length  of  the  I-beam  from  rods  anchored  in  plugs 
in  the  roof,  and  to  butt  the  upper  end  against  a  timber.  This  top  length 
is  curved,  to  allow  the  bucket  to  be  carried  high  enough  for  dumping 


SHAFTS  AND  RAISES  87 

into  a  car.  Because  of  the  fact  that  the  I-beam  does  not  sag  as  does  a 
rope,  larger  buckets  can  be  used  with  the  I-beam  equipment.  This  is 
a  great  advantage,  while  it  is  also  possible  to  continue  sinking  as  far  as 
desired;  with  a  rope  trolley  200  ft.  is  as  far  as  can  be  sunk  at  one  lift;  on 
the  other  hand  the  rope  method  may  be  cheaper. 

The  I-beams  are  fastened  together  by  top  and  bottom  plates,  so  as 
not  to  interfere  with  the  travel  of  the  trolley  against  the  webs  of  the  beam. 
Beams  20  ft.  long  are  used,  but  an  extension  piece  10  ft.  long  is  put  in 
until  the  shaft  can  be  worked  deep  enough  to  allow  the  use  of  a  regular 
length  of  track.  To  prevent  overrunning,  a  wooden  buffer  is  bolted 
to  the  I-beam.  In  order  to  get  a  binding  action  in  the  drill  holes  that 
carry  the  I-beams,  the  holes  are  put  in  at  right  angles  to  the  dip  of  the 
lode.  These  are  drilled  by  the  machines  as  the  shaft  is  being  sunk. 

In  shafts  where  a  rope  trolley  is  used,  the  bottom  end  of  the  rope  is 
fastened  to  an  eye-bolt  wedged  into  a  hole  about  2  ft.  deep  which  points 
back  into  the  shaft  so  that  the  harder  the  pull  the  more  the  bolt  is  forced 
into  the  hole.  At  the  upper  end  provision  must  be  made  for  stretching 
the  rope  so  that  there  will  be  as  little  sag  as  possible,  for  there  can  be  no 
supporting  of  the  trolley  cable  from  intermediate  points.  In  the  South 
Hecla  shaft  of  the  Calumet  &  Hecla  it  is  the  custom  to  do  the  final  tighten- 
ing of  the  trolley  cable  by  a  turnbuckle  having  a  travel  of  several  feet. 
This  is  seated  at  one  end  against  a  timber  running  from  the  foot  to  the 
hanging  wall,  while  the  other  is  fastened  by  a  clip  to  the  rope.  The  extra 
trolley  rope  is  carried  in  a  coil  out  of  the  way.  As  new  cable  is  required 
by  the  deepening  of  the  shaft,  the  clip  is  loosened  and  more  rope  is  let  out. 
Then  the  clip  is  bolted  on  again  and  after  pulling  the  cable  as  tight  as 
possible  with  the  hoisting  engine,  the  turnbuckle  is  used  to  do  the  final 
stretching. 

At  the  Mohawk  mines  the  upper  end  of  the  trolley  cable  is  bolted  to  a 
plate  which  is  fastened  to  a  bolt  through  a  timber  of  the  shaft.  By  tight- 
ening the  nut  on  this  bolt,  the  final  stretching  of  the  trolley  cable  is 
effected.  The  manner  of  fastening  this  clamp  to  the  rope  is  shown  in  the 
illustration.  There  are  two  screw-bolts  with  an  iron  pin  between  them 
to  put  a  kink  in  the  cable  and  tighten  it  after  the  two  U-bolts  have  been 
clamped  upon  it.  Even  when  tightening  as  much  as  is  practicable  on 
the  trolley  cable,  there  is  some  sag,  and  even  if  the  cable  can  be  carried 
nearer  the  roof  than  the  I-beam,  it  is  necessary  to  use  a  smaller  bucket 
with  the  rope  than  with  the  I-beam.  At  the  South  Hecla  the  sinking 
bucket  has  a  capacity  of  700  Ib.  of  rock. 

Whatever  the  method  of  carrying  the  trolley,  the  bucket  is  perma- 
nently attached  to  the  hoisting  cable  by  a  fall  that  permits  it  to  be  lowered 
to  the  rock  pile  in  the  shaft.  The  illustration  shows  the  rope  trolley 
used  at  the  Calumet  &  Hecla  mines.  The  air  hoist  may  be  installed 


88 


DETAILS  OF  PRACTICAL  MINING 


either  in  the  man  way  compartment  of  the  shaft  or  in  the  stations,  accord- 
ing to  the  preference  of  the  superintendent  in  charge  of  the  work.  But 
installing  the  hoist  in  the  shaft  does  away  with  the  necessity  of  placing 
a  sheave  at  the  top  around  which  the  hoisting  cable  is  passed. 

Hinge  for  Shaft  Doors  (By  Clinton  P.  Bernard)  .—While  sinking  is 
in  progress  it  is  usually  necessary  to  place  doors  over  the  shaft  at  the 
collar  for  preventing  muck  from  going  down,  and  for  carrying  the  rails  if 
the  material  be  dumped  into  a  car.  Fig.  76  shows  a  hinge  for  such  doors; 
it  can  be  made  by  any  blacksmith,  and  has  several  advantages  over  the 
ordinary  flat  hinge.  The  center  of  the  eye  is  set  level  with  the  rail  and 
away  from  the  edge  of  the  shaft  a  distance  equal  to  the  thickness  of  the 


PIG.    76. SHAFT  DOOR  WITH  WROUGHT  HINGE  OP  SPECIAL  DESIGN. 

door  plus  the  rail.  The  hinge  allows  a  close  joint  between  the  rails,  while 
the  door  in  a  vertical  position  is  entirely  clear  of  the  shaft,  and  when 
thrown  back  the  rails  are  superimposed,  thus  relieving  the  hinge  of  all 
strain.  The  door  half  of  the  hinge  has  a  bearing  on  the  collar  set  to 
give  added  stiffness  to  the  door. 

Sinking  an  Untimbered  Shaft. — The  method  of  sinking  shaft  No.  6  of 
the  St.  Louis  Smelting  &  Refining  Co.  in  Missouri  was  novel  in  that  it 
was  carried  down  through  limestone  for  557  ft.  without  timbering  and  by 
means  of  a  derrick  instead  of  a  headframe.  Air  pipe  was  not  installed  in 
permanent  form  until  the  completion  of  the  shaft.  No  pumping  was 
necessary,  and  only  some  slight  timbering,  where  the  limestone  was 
badly  shattered.  A  speed  of  100  ft.  per  month  was  maintained.  After 
the  bottom  was  reached,  timbering  was  done,  working  from  the  bottom 
up.  Electric  lights  were  strung  through  the  shaft  while  the  permanent 
timbers  and  pipe  were  being  set.  The  end  of  the  derrick  boom  also 


SHAFTS  AND  RAISES 


89 


carried  a  cluster  of  electric  lights  for  illuminating  the  ground  around  the 
collar  of  the  shaft.  Mucking  was  done  by  means  of  a  cluster  of  electric 
lamps  on  the  end  of  a  wire  raised  and  lowered  by  a  reel  at  the  collar.  To 
provide  against  failure  of  the  current,  two  torches  were  always  kept 
tied  to  the  bucket. 

Hanging  Bracket  for  Shaft  Platform. — In  sinking  the  Bennett  shaft 
on  the  Mesabi  range,  the  device  shown  in  Fig.  77  was  used  to  support  a 
hanging  platform,  in  cases  where  the  ground  could  be  left  open  for  some 


Round. 


' Hanger  Bolt 


12x12 
EndP/ate 


PIG.    77. — BRACKET  SUSPENDED  FROM  HANGER  BOLTS. 

distance  below  the  timbering  and  it  was  therefore  impossible  to  swing  a 
set  from  the  bottom.  Four  pieces  of  lj^-in.  round  iron,  the  same  that 
was  used  for  the  hanger  bolts,  were  bent  at  one  end  so  as  to  hook  around 
the  hanger  bolts  supporting  the  lowest  end  plate  and  then  drop  vertically 
over  the  side  of  the  end  plate.  The  other  ends  were  bent  to  form  loops 
of  the  proper  size  to  take  a  3-in.  pipe,  and  in  such  a  plane  that  the  pipe 
when  inserted  would  lie  parallel  to  the  wall  plates.  On  the  two  lengths 
of  pipe  inserted  in  the  four  brackets,  a  plank  platform  was  built  on 


90 


DETAILS  OF  PRACTICAL  MINING 


which  the  men  could  work  in  placing  the  new  set.  The  sets  were  spaced 
5  ft.  and  the  length  of  the  bracket,  8  ft.  overall,  was  sufficient  to  give 
plenty  of  clearance  below  the  new  set  and  room  to  work. 

Aligning  Concrete  Forms  in  Shaft  (By  Robert  H.  Dickson). — The 
Calumet  &  Arizona  Mining  Co.,  of  Bisbee,  in  relining  its  Junction  shaft 
started  at  the  bottom  and  replaced  the  timbers  with  concrete.  Since 
most  of  the  shaft  sets  had  been  in  place  for  10  years,  and  in  that  time 
moved  more  or  less  from  their  original  position,  permanent  points  had  to 
be  established  at  regular  intervals  in  the  shaft,  for  lining  in  the  concrete 
forms. 

A  preliminary  plumbing  was  done  in  order  to  ascertain  the  relative 
positions  of  the  sets,  and  thus  determine  the  best  position  for  the  perma- 


uc 4 ,Q" ^ 

PERMANENT  HANGER  FOR  LINING  FORMS 


PERMANENT 
HANGER  IN  POSITION 


FIG.    78. HANGERS  FOR  SHAFT  PLUMB  WIRES. 

nent  points.  This  plumbing  was  done  by  hanging  two  wires  in  opposite 
corners  of  the  shaft,  and  measuring  the  distances  from  them  to  the  wall 
plates  and  end  plates. 

The  permanent  points  were  placed  in  proper  position  by  hanging  two 
plumb  lines  the  full  length  of  the  shaft.  The  lines  were  manipulated 
over  hangers,  shown  in  Fig.  78.  These  hangers  were  first  set  by  hanging 
a  short  plumb  line  over  them,  and  adjusting  this  into  proper  position  by 
transit  and  tape.  They  were  held  by  a  5-in.  lagscrew  and  washer  to  a 
10  X  10-in.  stringer,  projecting  a  little  beyond  the  edge  of  the  shaft. 
The  %-in.  slot,  through  which  the  lagscrew  passed,  allowed  the  hanger 
to  be  moved  transversely  or  longitudinally,  and  thus  adjusted  to  exact 
position.  The  long  plumb  lines  of  piano  wire  were  then  hung  over  the 
hangers.  Each  line  was  1500  ft.  long  and  carried  a  60-lb.  weight  partly 
immersed  in  crude  oil. 


SHAFTS  AND  RAISES  91 

There  was  a  strong  upward  draft  in  the  shaft,  due  to  the  hot  steam 
pipes  supplying  the  pumps,  which  caused  troublesome  vibration  of  the 
wires.  An  ingenious  scheme  was  devised  by  E.  E.  Whitely,  chief  engi- 
neer of  the  company,  to  minimize  this  vibration.  It  consisted  of  finding 
the  center  of  swing  of  the  wire  at  intervals  of  300  ft.  and  then  fasten- 
ing it  in  this  position.  A  strip  of  wood  about  J£  X  1  X  12  in.,  with  a 
j^JL6-in.  hole  near  one  end,  slotted  to  insert  the  wire,  was  set  so  that  the 
wire  vibrated  in  the  hole  without  touching  the  sides.  When  the  center 
of  vibration  was  at  the  center  of  the  hole,  the  strip  was  nailed  to  the  wall 
plate,  and  two  halves  of  a  pencil  about  2  in.  long,  with  the  lead  removed, 
were  placed  in  the  hole  so  that  the  wire  passed  through  the  groove  left 
by  the  head,  thus  holding  the  wire  fast  in  place. 

The  next  step  consisted  in  placing  permanent  points  or  hangers  at 
35-ft.  intervals.  Their  construction  is  also  shown.  They  were  made 
of  J^-in.  iron  plate  sheared  into  strips  A,  1%  X  10  in.  One  end  of  one 
edge  of  the  strip  was  milled  for  a  distance  of  %  in.  back  and  in  this  a  file- 
cut  B  was  made  so  as  to  be  vertical  when  the  hanger  was  in  place.  The 
other  end  of  the  strip  was  slotted  at  C.  Two  of  these  were  placed  at 
each  35-ft.  interval  in  opposite  ends  of  the  shaft  but  near  the  same  wall 
plate.-  They  were  fastened  to  the  wall  plate  by  lagscrews  through  the 
slot  C  so  that  the  wire  passed  through  the  little  slot  B.  By  means  of 
the  washer  D  with  a  screw  through  the  J^-in.  hole  E,  the  hanger  was 
held  firmly  to  the  timber  so  as  not  to  rotate  about  the  screw  through  C. 
For  actually  lining  in  the  concrete  forms,  a  copper  wire  with  a  10-lb. 
plumb  bob  was  fastened  to  a  post  or  other  timber,  as  shown,  and  then 
let  down  through  the  slot  B.  As  the  work  proceeded  upward,  the  hangers 
were  taken  out  with  the  timbers  and  the  next  set  above  used. 

Setting  Timbers  in  Vertical  Shafts  (By  C.  W.  Macdougall). — The 
following  method  of  setting  timber  in  a  vertical  shaft  was  used  during 
practically  the  entire  sinking  period  of  one  of  the  largest  shafts  in  the 
Michigan  copper  country,  and  was  found  thoroughly  reliable.  It 
possesses  certain  advantages  over  the  usual  method. 

The  shaft  in  question  is  about  4000  ft.  deep  with  a  rock  section  of 
about  10  X  31  ft.,  or  9  X  30  ft.  outside  the  timbers,  and  has  four  hoisting 
compartments  besides  a  ladderway.  The  long  axis  of  the  shaft  lies 
about  north  and  south.  All  plates  are  12  X  12  in.  and  the  dividers 
10  X  12  in.;  the  hoisting  compartments  are  5  ft.  2  in.  by  7  ft.  overall  and 
4  ft.  4  in.  between  the  guides.  The  guides  are  5  X  8  in.,  with  a  groove 
2  in.  wide  and  1%  in.  deep  down  the  center.  The  framing  of  all  the  tim- 
ber was  done  from  templates. 

A  vertical  saw-mark  was  made  on  the  inside  of  the  wall  and  end  plates, 
that  on  the  wall  plate  being  in  the  center  of  the  timber,  and,  that  on  the 


92 


DETAILS  OF  PRACTICAL  MINING 


end  plate  being  4  ft.  from  the  foot-wall  end,  so  that  the  lines  would  clear 
the  guides. 

The  sets  were  hung  and  temporarily  blocked  approximately  in  place 
in  succession,  and  when  all  that  were  required  had  been  assembled,  plumb 
lines  were  dropped  as  shown  in  Fig.  79  at  points  A,  B,  C,  D,  from  reference 
points  in  the  sets  previously  placed  above.  Each  set  was  then  shifted 
by  means  of  wedges  at  the  four  corners  until  the  saw  marks  on  the  timbers 
were  in  line  with  the  plumb  lines,  this  being  determined  by  means  of 
an  ordinary  carpenter's  square,  held  as  shown  at  A.  After  the  four 
corners  were  blocked  into  place,  a  line  was  stretched  the  full  length  of  the 
shaft  from  B  to  D,  just  above  the  tops  of  the  dividers.  The  set  was  then 
blocked  at  points  opposite  the  ends  of  the  dividers  until  the  east  side  of 
the  guide  studdle  on  each  divider  was  2  in.  from  the  line.  The  object 
of  having  the  lines  stretched  from  B  to  D  and  taking  measurements  on 
each  divider  was  to  keep  the  wall  plates  from  bending  in  the  middle,  as 
they  would  if  the  wedges  were  not  driven  evenly  on  both  sides  of  the  shaft. 


mK 


Orooe 


-$o'- 

ARRMSGEMENTOF  SHA.FTSET  PLUMB  BOB 

FIG.    79. METHOD  EMPLOYED  FOR  LINING  UP  SHAFT  TIMBERS. 


By  using  this  method,  the  distance  the  plumb  lines  were  hung  from 
the  inside  face  of  the  timbers  was  immaterial,  the  practice  in  this  case 
being  to  hang  the  lines  from  60-d.  nails  about  3  in.  from  the  timber  and 
to  use  4-lb.  plumb  bobs,  of  the  design  shown,  for  weights,  the  plumb  lines 
being  of  No.  30  trot  line,  corresponding  to  a  heavy  mason's  line.  The 
reference  points  by  which  the  plumb  lines  were  set  were  copper  tacks 
with  their  heads  flattened  until  parallel  with  the  long  axis  of  the  shank, 
these  points  being  marked  by  aluminum  tags  nailed  to  the  timbers  just 
over  them.  This  method  of  lining  up  the  timbers  proved  to  be  far 
quicker  than  the  method  of  hanging  the  lines  in  the  four  corners  of  the 
shaft  and  using  wooden  blocks  for  gages,  for  the  wooden  blocks  would 
invariably  touch  a  line,  set  it  swinging  and  make  it  necessary  to  steady 
it  again,  costing  considerable  time;  whereas,  in  the  method  shown,  the 
lines  were  seldom  disturbed  and  there  was  far  less  danger  of  error. 

Light  Shaft  Timbering  (By  Harold  A.  Linke). — A  convenient  size 
for  a  vertical,  two-compartment,  exploratory  shaft  is  3  ft.  6  in.  by  7  ft. 
8  in.  inside  timbers.  The  excavation  for  a  shaft  of  this  size  measures 


SHAFTS  AND  RAISES 


93 


about  5  X  9  ft.,  is  of  minimum  cross-section  for  convenience  and  still 
large  enough  to  permit  drilling  to  sufficient  depth  for  economical  work. 

The  problem  of  timbering  a  shaft  is  governed  by  local  conditions.  In 
case  the  ground  is  not  heavy  and  stands  well,  where  only  occasional 
lagging  is  required  and  where  the  shaft  sets  serve  mainly  as  support  for 
the  guides,  ladders,  pipe,  etc.,  the  sets  shown  in  Fig.  80  at  1  answer  every 
purpose.  The  joint  is  detailed  in  2.  The  ends  of  the  posts  for  this  set 
require  no  special  framing  other  than  squaring.  If,  however,  all  avail- 
able strength  of  set  timbers  is  required,  then  it  is  advisable  to  frame  as 
shown  either  in  3  or  in  4.  The  end  of  a  post  for  a  set  framed  in  this 
manner  is  detailed  in  5.  In  6  are  shown  the  details  of  a  divider. 


FIG.    80. SHAFT  SET  OF  LIGHT  TIMBER  AND  DETAILS  OF  JOINTS. 

When  lumber  is  to  be  transported  by  rail  for  any  considerable  distance 
it  will  be  found  that  the  laid-down  price  of,  say,  6  X  6-in.,  S1S1E  is  much 
lower  than  6  X  6-in.  rough;  that  is  to  say,  the  saving  in  transportation 
on  weight  removed  in  surfacing  more  than  compensates  for  the  cost  of 
dressing.  The  details  2  to  6  are  dimensioned  for  6  X  6-in.  S1S1E,  which 
usually  measures  5J^  to  5%  in.  square. 

Diagonal  End  Plates,  Inclined  Shaft  (By  G.  A.  Denny). — For  a 
Mexican  shaft,  inclined  at  65°,  there  was  used  in  the  first  stages  the 
usual  type  of  timbering.  The  hanging  in  the  shaft,  however,  was  found 
exceedingly  heavy  and  hard  to  support,  and  to  overcome  this  difficulty 
the  system  of  timbering  shown  in  Fig.  81  was  designed.  This  proved  to 
be  altogether  superior  to  the  first  timbering  and  easily  sustained  the  pres- 
sure put  upon  it  by  the  heavy  ground. 

The  principal  difference  between  the  two  systems  of  timbering  is,  of 


94 


DETAILS  OF  PRACTICAL  MINING 


SHAFTS  AND  RAISES 


95 


course,  the  substitution  of  the  diagonal  end  plates  for  the  right-angled. 
The  bearers,  however,  are  put  in  parallel  to  the  wall  plates  in  the  new 
system  and  parallel  to  the  end  plates  in  the  old. 

TABLE  I. — TIMBER  LIST  OF  COLLAR,  ORDINARY  AND  BEARER  SETS  OF  OLD  SYSTEM 


No.  per  set 

Size 

Length 

Material 

Description 

2 

12  X  12" 

20'    0' 

Pine 

Wall  plates,  collar  set. 

2 

12  X  12" 

4'    6 

Pine 

End  plates,  collar  set. 

2 

6  X  12" 

4'    6 

Pine 

Dividers,  collar  set. 

4 

\Y\"  diam. 

6'    24" 

Wrt.  iron 

Tie  bolts,  collar  set. 

8 

1"  diam. 

3'    2 

Wrt.  iron 

Hanging  bolts,  collar  set. 

2 

8  X    8" 

14'    6 

Pine 

Wall  plates,  shaft  set. 

2 

8  X    8" 

5'    6 

Pine 

End  plates,  shaft  set. 

2 

6  X  10" 

4'    6 

Pine 

Dividers,  shaft  set. 

4 

8  X    8" 

4'    6 

Pine 

Corner  studdles,  shaft  set. 

4 

4  X  10" 

4'    6 

Pine 

Intermediate  studdles,  shaft  set 

8 

1"  diam. 

2'  10 

Wrt.  iron 

Hanging  bolts,  shaft  set. 

2 

8  X     8" 

14'    6 

Pine 

Wall  plates,  bearer  set. 

2 

8  X    8" 

5'    6 

Pine 

End  plates,  bearer  set. 

2 

8  X    8" 

8'    6 

Pine 

Bearers,  bearer  set. 

2 

6  X  10" 

4'    6 

Pine 

Dividers,  bearer  set. 

4 

8  X    8" 

4'    0 

Pine 

Corner  studdles,  bearer  set. 

4 

4  X  10" 

4'    6 

Pine 

Intermediate  studdles,  bearer  set. 

8 

1"  diam. 

2'  10 

Wrt.  iron 

Hanging  bolts,  bearer  set. 

TABLE  II. — TIMBER  LIST  OF  ORDINARY  AND  BEARER  SETS  IN  NEW  SYSTEM 


No.  per  set 

Mark 

Size 

Length 

Material 

Description 

2 

A 

8  X8" 

9'  10" 

Pine 

Wall  plates,  shaft  set. 

4 

B 

8  X  8" 

4'  10%2" 

Pine 

End  diagonals,  shaft  set. 

2 

E 

6X  8" 

4'  10^2'/ 

Pine 

Intermediate  diagonals,  shaft  set. 

4 

D 

8  X  8" 

3'  10H" 

Pine 

Corner  studdles,  shaft  set. 

2 

C 

6  X  8" 

3'    8^" 

Pine 

Intermediate  studdles,  shaft  set. 

8 

H 

1"  diam. 

2'    59ie" 

Wrt.  iron 

Hanging  bolts,  shaft  set. 

2 

F 

8  X  8" 

14'    0" 

Pine 

Wall  plates,  bearer  set. 

4 

B 

8  X  8" 

4'  105*2" 

Pine 

End  diagonals,  bearer  set. 

2 

E 

6X  8" 

4'  10^2" 

Pine 

Intermediate  diagonals,  bearer  set. 

8 

G 

8  X  8" 

3'    9?$" 

Pine 

Corner  studdles,  bearer  set. 

2 

C 

6  X  8" 

3'    8M" 

Pine 

Intermediate  studdles,  bearer  set. 

8 

H 

1"  diam. 

2'    5%6" 

Wrt.  iron 

Hanging  bolts,  bearer  set. 

Table  I  gives  the  bill  of  materials  for  sets  of  the  first  system  and 
Table  II  gives  it  for  the  new  system. 

Manway  and  Skipway  Door. — The  Bennett  shaft  near  Keewatin  on 
the  Mesabi  range  is  divided  into  a  combination  man-  and  pipeway  and 
two  skipways,  arranged  in  a  row.  A  vertical  partition  or  brattice  of 
2-in.  planks  separates  the  man  way  from  the  adjacent  skipway.  The 
shaft  sets  are  spaced  5  ft.  and  on  every  third  set  a  sollar  is  built  of  2-in. 
planks  laid  on  2  X  6-in.  joists  parallel  to  the  end  plates.  Repair  work 
on  the  pipes  necessitates  the  lowering  of  material  and  tools,  which  or- 


96 


DETAILS  OF  PRACTICAL  MINING 


dinarily  must  be  carried  down  by  hand  or  slung  from  sollar  to  sollar.  To 
enable  such  supplies  to  be  lowered  in  the  skip  and  taken  into  the  manway, 
a  door  has  been  provided  in  the  brattice  at  each  sollar.  The  ladder  open- 
ing in  the  sollar  is  2  ft.  square,  situated  in  a  corner  next  to  the  skipway. 
The  door  occupies  the  place  of  the  second  and  third  brattice  boards  and 
is  hinged  at  the  bottom  so  as  to  cover  most  of  the  ladder  opening  when  it 
is  swung  down.  It  is  3  ft.  10  in.  long  and  its  top  comes  even  with  the 
center  of  the  set  above  the  sollar  set.  It  is  held  closed  against  the  divider 


Guide 


Wall  Plate 


Support 


Wa// Plate 


MferHcal  Section  A- A 


Showing  Door  Closed 
FIO.    82. CORNER  OF  MANWAY  COMPARTMENT. 

of  this  set  by  a  wedge  made  out  of  a  2  X  4-in.  piece,  slipping  through  a 
1  X  4-in.  slot  in  another  2  X  4-in.  piece  spiked  horizontally  to  the  brat- 
tice and  divider.  A  2  X  2-in.  filler  is  nailed  to  the  top  of  the  2  X  6-in. 
sollar  joist  next  to  the  skipway,  in  order  to  bring  the  bottom  of  the  door 
flush  with  the  sollar  floor.  It  is  shown  closed  in  the  lower  part  of  Fig. 
82  and  swung  down  in  the  upper  part  of  the  same  illustration. 

Inclined  Shaft  for  Timber  (By  L.  D.  Davenport). — For  a  small  mine 
on  the  Mesabi,  where  the  overburden  is  shallow,  the  inclined  timber  shaft 
or  timber  slide  seems  to  have  several  advantages  over  the  vertical  shaft 
generally  used  for  this  purpose.  Only  one  top  man  is  required  to  send 


SHAFTS  AND  RAISES 


97 


down  timber  instead  of  two;  no  rope,  windlass,  or  headframe  is  needed; 
and  an  easy,  safe  entrance  to  the  mine  is  had. 

This  description  applies  to  the  latest  inclined  timber  shaft  sunk  by 
the  Oliver  Iron  Mining  Co.,  although  there  are  a  number  of  inclines  in 
use  at  other  mines  in  this  district  which  are  similar.  Such  a  shaft  has 
to  serve  two  levels.  Fig.  83  shows  the  arrangement  of  the  sets  where  the 
incline  intersects  the  top  sublevel.  A  door  made  of  double  thickness  of 
2-in.  plank  deflects  the  descending  timber  or  lagging  to  the  top  sublevel. 
When  it  is  desired  to  send  timber  to  the  lower  level  this  door  is  raised  by 
means  of  a  block  and  tackle  fastened  to  one  of  the  caps  as  shown.  The 
free  end  of  the  rope  is  led  to  the  stairway  side  of  the  shaft,  where  it  is 
pulled.  A  vertical  ladder  against  the  side  of  the  shaft  connects  the  sub- 


Block  and 


Door  hinged  at  A" is 
raised  when  timber  is 
sent  to  lower  level 


Ladder  on  Manwqy 
Side  of  Shaft 


FIG.    83. ARRANGEMENT  OF  TIMBERING  AT  SUBLEVEL. 

level  and  the  stairway.  Fig.  84  shows  the  details  of  the  shaft  timbering, 
the  stairway  and  the  timber  slide.  This  shaft  has  a  dip  of  35°  and  is 
110  ft.  deep  along  the  slope.  Timber  travels  down  the  slide  faster  than 
is  necessary.  In  another  mine  the  timber  tends  to  hang  up  on  a  90-ft. 
incline  which  dips  at  29°. 

Fig.  85  shows  the  details  of  the  headframe  used  in  sinking  the 
shaft.  Two  9  X  16-in.  by  28-ft.  timbers  supported  by  two  bents  of 
round  timber  carried  the  rails.  The  dump  was  made  of  6  X  8-in.  timber 
faced  with  %  X  3-in.  flat  iron.  The  skip  was  made  from  a  tram-car  box 
with  the  end  door  removed  and  bail  and  wheels  fitted  to  it.  The  rear 
wheels  had  a  wide  tread  to  pass  the  dump  and  the  sides  of  the  box  were 
cut  back  as  shown. 

The  shaft  was  sunk  through  the  overburden  to  the  ore.     To  avoid 

7 


98 


DETAILS  OF  PRACTICAL  MINING 


hoisting  any  ore  a  raise  was  holed  through  from  below  and  trimmed 
out;  the  timbering  was  then  carried  to  the  bottom.  When  the  shaft  was 
completed  the  headframe  was  removed  and  a  small  shed  with  three  walls 
and  a  roof  was  built  over  the  collar. 

Unwatering  and  Equipping  Un timbered  Shaft  (By  Douglas  Muir). — 
Unwatering  the  Rayas  mine  of  the  Guanajuato  Reduction  &  Mines  Co., 
at  Guanajuato,  Mexico,  was  performed  by  bailing  through  the  old  Rayas 
main  shaft.  This  shaft  is  circular  in  plan  and  has  a  minimum  diameter 
of  36  ft.,  the  usual  diameter  being  40  ft.  A  tunnel  driven  for  drainage 
purposes  cut  the  shaft  269  ft.  below  the  surface  and  was  chosen  as  the 
discharge  point  for  the  bailers.  One  steam  and  one  electric  hoist  were 
used  for  the  bailing,  handling  four  bailers  in  all.  At  the  time  of  be- 
ginning work,  the  water  stood  770  ft.  below  the  shaft  collar,  leaving  495 
ft.  to  be  unwatered. 


o'. 

SKWN  THROU6H  SHAFT 
PERPENDICULAR  TO  DIP 

FIG.    84. DETAILS  OF  SHAFT 

TIMBERING. 


,_7v~->r 

FIG.    85. HEADFRAME    USED  IN  SINKING. 


Plumb  lines  were  dropped  from  the  sheaves  of  the  two  hoists  to  deter- 
mine the  exact  plane  of  the  wire-rope  guides  on  which  the  bailers  were  to 
run.  From  the  plane  thus  determined,  the  framework  backstops  A, 
Fig.  86,  for  receiving  the  kick-back  from  the  bailers  on  discharging, 
and  the  apron  decks  for  receiving  and  carrying  off  the  water,  were  located, 
proper  clearance  for  passing  of  the  bailers  being  allowed.  To  support 
these  structures,  holes  were  drilled  in  the  sides  of  the  shaft  and  IJ^-in. 
eye-bolts  were  wedge-driven  and  cemented  into  them.  From  these  eye- 
bolts  heavy  wire  cables  were  stretched  across  the  shaft  and  tightened  by 
turnbuckles,  thus  giving  a  support  on  which  to  lash  planks  to  work 
from.  The  timber  frames  A  of  8  X  8-in.  material  were  erected  back  of 
and  parallel  to  the  plane  of  each  set  of  guides  to  form  the  backstops. 
These  frames  spanned  the  distance  between  the  two  outside  guides  and 
were  16  ft.  high,  allowing  for  a  considerable  error  in  overwinding  so  that 
if  such  occurred,  the  bailer  would  not  swing  back  toward  the  center  of 
the  shaft  and  strike  the  top  of  the  backstop  on  its  return  trip  downward. 


SHAFTS  AND  RAISES 


99 


The  frames  were  suspended  from  heavy  eye-bolts  in  the  sides  of  the  shaft 
30  ft.  above,  thus  giving  a  nearly  vertical  pull  at  the  supporting  points. 
On  the  faces  of  these  frames  were  spiked  blocks  of  wood  and  across  these 
blocks  were  nailed  3-in.  planks  B  to  receive  the  blow  of  the  discharging 


FIG.    Sb. — BAILERS,  BACKSTOPS,  DISCHARGE  APRON  AND  TEMPORARY  GUIDE  ANCHORAGES 


bailer.  Clearances  of  9  in.  were  left  between  the  back  of  the  bailer  and 
the  face  of  these  planks  and  between  the  front  of  the  bailer  and  the 
edge  of  the  discharge  apron,  these  small  clearances  insuring  a  minimum 
spilling  of  water.  During  rapid  running,  the  swing  set  up  in  the  guides 


100  DETAILS  OF  PRACTICAL  MINING 

often  brought  a  bailer  into  violent  contact  with  the  planks.  These 
were  knocked  off  and  no  damage  done  to  the  bailer,  which  would  not  have 
been  the  case  with  a  rigidly  braced  frame  placed  close  to  the  bailer  and 
without  the  rather  loose  planks. 

The  discharge  decks  were  built  of  2-in.  planks  on  a  6  X  6-in.  frame 
hung  from  the  side  of  the  shaft,  spanning  the  distance  between  the  two 
outside  guides  and  having  a  steep  slope  to  carry  off  the  water  quickly. 

The  guides  are  %-in.  galvanized  wire  rope.  The  drums  on  which 
they  were  carried  were  placed  near  the  shaft  at  the  surface,  the  ends  of 
the  ropes  passed  through  clamps  to  hold  them,  and  the  ropes  laid  out 
until  the  ends  reached  the  discharge  station  269  ft.  down.  The  guides 
for  each  bailer  are  spaced  4  ft.  6  in.,  with  a  2-ft.  10-in.  clearance  between 
inside  guides  of  the  pair  electrically  operated  and  a  3-ft.  5-in.  clearance 
for  the  steam-operated  pair,  since  the  latter  were  longer  and  heavier  bail- 
ers and  had  more  movement  when  in  action.  Rocks  weighing  about  a 
ton  each  were  drilled  for  eye-bolts,  clamped  one  to  each  guide  end  at  the 
discharge  station  and  swung  out  into  the  shaft.  Two  8  X  8-in.  timbers 
were  notched  to  match  the  spacing  of  each  set  of  four  guides  and  clamped 
to  them  by  bolts  passing  through  the  timbers  as  shown  at  C,  Fig.  86. 
The  notches  for  the  middle  guides  were  made  large,  to  allow  them  with 
their  weights  to  be  lowered  one  at  a  time  by  sliding  freely  through  the 
timbers.  The  two  outside  guides  with  their  weights  were  clamped 
tight  to  the  timbers  as  a  single  unit. 

The  work  of  lowering  the  guides  was  carried  out  as  follows:  Each 
middle  guide  was  clamped  to  a  hoisting  cable  at  a  point  below  its  sheave 
and  lowered  independently,  sliding  through  the  timbers  kept  hanging  at 
the  discharge  station  by  the  outside  guides.  When  the  end  of  the  hoist- 
ing cable  reached  these  timbers,  the  guide  was  made  fast  on  the  surface, 
the  hoisting  cable  raised  and  the  operation  repeated  until  the  two  sus- 
pended rocks  were  about  115  ft.  below  the  surface  of  the  water.  One 
hoisting  cable  was  then  unwound  down  the  shaft  and  wound  back  on 
its  hoist  drum  in  the  same  direction  as  the  other  cable  and  the  drums 
clutched  in  so  as  to  have  two  cables  to  lower  by  at  the  same  time.  The 
hoisting  cables  were  clamped  simultaneously  to  the  two  outside  guides, 
which  were  then  lowered  at  the  same  time,  in  the  same  manner  as  de- 
scribed for  the  single  guides.  These  guides  were  lowered  until  the 
clamping  timbers  were  about  100  ft.  below  the  surface  of  the  water  and 
15  ft.  above  the  rocks  on  the  middle  independent  guides.  When  bailing 
had  lowered  the  water-level  nearly  to  the  timbers,  the  guides  were  lowered 
another  100  ft.  In  lowering,  the  slack  on  the  guides  from  their  drums  to 
the  discharge  station  was  handled  and  held  by  taking  two  wra^>s  of  guide 
cable  around  the  hoist  drum  over  the  layers  of  hoisting  cable  already 
there. 


SHAFTS  AND  RAISES  101 

The  bailers  on  the  steam  hoist  had  a  capacity  of  1015  gal.  net  and  the 
electric  bailers  575  gal.  They  were  built  of  No.  14  galvanized  sheet 
iron,  riveted  in  the  form  of  a  cylinder,  having  heads  and  bottoms  of  double 
2-in.  plank,  fastened  in  by  large  wood  screws.  They  were  bound  with 
bands  of  %  X  2-in.  strap  iron  for  stiffening,  and  slung  on  the  hoisting 
cables  by  means  of  a  harness  of  iron  rods  and  a  bridle  as  shown  in  Fig. 
86,  representing  a  bailer  of  each  size  hanging  at  the  discharge  station. 
The  bottom  of  the  bailer  had  a  12  X  14-in.  hole  for  an  intake,  over  which 
was  a  hinged  leather-covered  door  of  mesquite.  In  the  side  at  the  bottom 
was  a  10  X  10-in.  hole  to  which  was  fitted  a  frame  carrying  a  similar  door 
E  for  discharge.  The  discharge  door  was  connected  by  a  J^~m-  iron 
rod  F  to  one  end  of  a  lever  G  mounted  on  top  of  the  bailer.  The  other 
end  of  this  lever  was  split  and  ran  on  the  outside  guide  so  as  to  engage  the 
tripping  weight  D  and  effect  the  discharge.  The  tripping  weight  was 
a  block  of  oak,  slotted  to  fit  on  the  guide,  on  which  it  slid  loose,  being 
hung  from  above  by  a  small  wire  cable.  In  case  the  hoistman  pulled 
by  the  discharge  point,  the  weight  was  simply  carried  up  along  the  guide 
and  no  damage  done  to  the  bailer.  The  guide  blocks  for  the  bailers  were 
of  cast  zinc,  in  two  halves,  held  in  strap-iron  frames  bolted  to  3-in. 
wooden  extension  pieces.  On  the  bottoms  of  the  bailers  were  cones  of 
J£-m.  sheet  iron  perforated  with  1-in.  holes,  sufficient  in  number  to  give 
an  area  exceeding  that  of  the  intake  door.  These  cones  did  away  with 
all  jar  as  the  bailers  struck  the  surface  of  the  water. 

A  gin  pole,  mounted  on  the  surface  at  the  edge  of  the  shaft,  fitted 
with  pulley  and  cable  running  to  a  geared  winch,  was  used  for  removing 
the  bailers  from  the  shaft  for  repairs,  spare  bailers  being  kept  in  readi- 
ness for  instant  changing.1 

In  July,  an  average  month,  39,000,000  gal.  of  water  was  raised  an 
average  distance  of  568  ft.  at  a  cost  of  about  Koo  ct.  per  gallon.  The 
mine  was  unwatered  on  Sept.  15,  after  removing  about  150,000,000  gal. 
of  water.  Four  and  a  half  months  of  rapid,  continuous  bailing  ac- 
complished the  task. 

Upon  completion  of  the  unwatering,  the  work  of  equipping  the 
shaft  was  begun  at  once.  The  rock  weights  and  bottom  timbers  were 
removed  and  the  guides  anchored  well  below  the  bottom  station  as  shown 
at  A  in  Fig.  87.  At  the  surface,  eye-bolts  of  1%-m.  iron,  threaded  for 
3  ft.  for  tightening  the  guides,  were  hung  through  plates  on  the  headframe, 
a  structure  built  of  steel  shapes  flat  over  the  collar  of  the  shaft,  and  the 
guides  drawn  tight  with  them. 

An  11  X  11-ft.  crosscut  tunnel  was  driven  from  the  grade  of  the  mill 
electric  railway,  to  pass  by  the  shaft  at  a  distance  of  20  ft.  At  a  point 
opposite  the  shaft,  a  raise  8  X  15  ft.  in  section  was  driven  for  30  ft., 
forming  an  ore  pocket  for  delivering  ore  to  the  cars,  ,and  from  the  top  of 


102 


DETAILS  OF  PRACTICAL  MINING 


FIG.    87. STATION    FOR    DISCHARGING    ORE    CARS,    MANWAY    STATION    AND    PERMANENT 

ANCHORAGE  FOR  ROPE  GUIDES. 


SHAFTS  AND  RAISES  103 

the  raise  a  short  crosscut  7  X  15  ft.  in  section  was  driven  to  cut  the  shaft. 
From  the  main  crosscut,  another  small  road  was  driven  to  the  shaft  for 
handling  men  and  supplies.  On  breaking  through,  a  timber  platform 
was  hung  in  the  shaft  in  front  of  each  connection  point  in  order  to  catch 
the  rock  which  otherwise  would  have  fallen  down  the  shaft  and  wrecked 
the  discharge  station.  Both  entrances  to  the  shaft  were  arched  with  cut 
stone  laid  in  cement  mortar.  The  shaft  was  equipped  for  hoisting  ore 
with  the  electric  hoist  only. 

In  front  of  the  crosscut  to  the  top  of  the  ore  pocket  a  truss  of  10  X  10- 
in.  timber  was  hung,  back  of  the  guides  and  parallel  to  their  plane, 
by  means  of  1^-in.  rods  to  the  end  points  of  the  top  and  bottom  chords. 
These  rods  had  turnbuckles,  and  were  fastened  by  plate  clevises  to  1  J^-in. 
eye-bolts  placed  in  the  sides  of  the  shaft  9  ft.  above  the  top  chord  of  the 
truss.  To  the  bottom  chord  10  X  10-in.  timbers  were  bolted  and  seated 
in  hitches  in  the  side  of  the  shaft.  On  this  structure  were  placed  the 
rigid-frame  guides  into  which  the  cages  run  at  landing,  the  chairs  for 
landing,  and  the  decking  for  the  cars.  In  front  of  the  manway  opening, 
a  platform  was  hung  in  the  shaft  extending  to  meet  the  edge  of  the  cage. 

Owing  to  the  fact  that  the  stations  below  were  situated  on  the  op- 
posite sides  of  the  shaft,  it  was  necessary  that  at  one  of  them  the  mine 
cars  cross  the  shaft  to  reach  the  cage.  Two  trusses  were  hung  in  the  shaft 
to  form  a  bridge  for  tramming  across  to  the  cage,  the  cars  entering  the 
cage  from  one  side  and  leaving  it  from  the  other.  The  trusses  were 
hung  similarly  to  the  one  described. 

CONCRETE  SHAFT  LINING 

Concrete  Lining  of  the  Kingdon  Shaft  (By  Charles  B.  Eades  and  F.  E. 
Calkins). — The  reinforced-concrete  lining  of  the  two-compartment  King- 
don shaft  of  the  Old  Dominion  Co.,  at  Globe,  Ariz.,  completed  on  Aug. 
28,  1912,  extends  from  the  collar  to  the  bottom  of  the  shaft,  a  distance 
of  1017  ft.  In  October,  1911,  the  timbering  of  this  shaft  was  destroyed 
by  fire,  and  it  was  decided  to  put  in  a  concrete  lining  by  lifts  or  sections, 
beginning  near  the  top  and  working  downward;  the  work  was  finally 
accomplished  in  six  sections,  from  150  to  220  ft.  in  height,  depending  on 
the  condition  of  the  ground.  The  work  was  done  by  contract. 

About  a  month  was  spent  in  the  preliminary  work  of  erecting  a  tem- 
porary headframe,  crushing  plant,  concrete  mixer,  etc.,  and  in  cleaning 
down  the  charred  timbers  and  loose  rock  from  the  first  section,  extending 
from  the  collar  to  a  point  .160  ft.  below.  Two  specially  built,  heavy, 
wooden  cages  swinging  freely  in  the  shaft  were  used  throughout  the 
work.  In  lining  a  section,  the  walls  were  stripped  of  charred  timber 
and  loose  rock,  beginning  at  the  top  and  working  downward,  and  light 


104 


DETAILS  OF  PRACTICAL  MINING 


Rock  and 
•Sand  Bins 


'ensuring  Bucke  fs 

l*ing  Machine 
"ixing  Platform 
A — '~  DQ/iv&ri  tin 

I     T    ° 


Clamp 
s/ee  ves. 
Plain 
ends  of 
pipes 
butf-jng 


'b.Ra!ls,var'ied  ~~1 


Temporary^ 
Timbering  J 


'eceivlng    ^ 
hopper 


Receiving 
Hopper< 

-•Working— ^ 


'SECTION  OF        ^ 

|  WALL  A.TCAVED 
PORTIONS 


FIG.    88. — CONCRETING  THE  KINGDON  SHAFT  AT  GLOBE,  ARIZ. 


SHAFTS  AND  RAISES  105 

temporary  sets  of  timber  put  in,  with  a  few  lagging  pieces  wherever 
necessary,  so  that  the  men  were  always  protected  from  falling  ground. 
The  general  layout  and  design  of  the  lining  is  shown  in  Fig.  88. 

When  the  bottom  of  the  section  was  reached,  temporary  timber 
bearers  were  placed  along  the  sides  and  ends  and  across  the  center  of  the 
shaft,  forms  were  built  upon  them,  and  a  permanent  reinforced-concrete 
bearer,  4  or  5  ft.  high,  was  put  in.  Two  or  three  days  were  allowed  for 
this  to  set,  after  which  the  concrete  lining  was  built  up  on  top  of  it.  The 
forms  were  built  in  sections  12  ft.  high,  and  the  concrete  poured  in 
between  the  form  and  the  rock  walls  of  the  shaft.  As  soon  as  one  12-ft. 
section  was  filled,  another  was  erected  on  top  of  it,  plumbed  and  blocked, 
and  filled  with  concrete  in  the  same  manner.  The  work  proceeded 
thus  until  the  bottom  of  the  finished  lining  above  was  reached,  the 
temporary  timbering  being  removed  as  fast  as  the  forms  were  erected. 

The  concrete  was  made  to  run  from  the  conical  mixer  at  the  surface 
into  a  hopper  and  down  the  shaft  through  a  4-in.  iron  pipe  to  the  point 
where  it  was  needed;  there  it  was  caught  in  an  ordinary  steel  sinking 
bucket  suspended  from  the  finished  portion  of  the  lining  above,  and 
allowed  to  run  through  a  hole  cut  in  the  side  of  the  bucket  a  few  inches 
above  the  bottom,  and  through  a  short  steel  chute  into  the  forms.  This 
was  an  efficient  and  flexible  arrangement,  as  the  bucket  could  be  easily 
swung  or  turned  and  a  continuous  stream  of  concrete  directed  to  any 
part  of  the  forms  desired.  The  concrete  was  successfully  dropped  in 
this  manner  for  a  distance  of  over  1000  ft.  in  building  the  last  section. 
Its  falling  velocity  was  but  little  greater  through  the  pipe  to  the  deepest 
part  of  the  shaft  than  to  the  sections  near  the  surface,  provided  the 
mixture  was  fed  regularly  and  the  upper  end  of  the  pipe  closed  at  the  end 
of  each  batch.  This  was  easily  done  by  placing  a  piece  of  canvas  over  the 
opening,  thus  stopping  the  air  current  in  the  pipe,  checking  the  velocity 
of  the  concrete,  and  tending  to  break  it  up  into  smaller  pieces,  which 
fell  with  less  force. 

The  forms  used  were  of  2-in.  lumber  dressed  to  uniform  thickness. 
They  were  set  up  by  placing  4  X  4-in.  posts  in  the  corners  of  each  com- 
partment, with  one  4  X  6-in.  post  between  corners  on  the  5-ft.  side  and 
two  on  the  7-ft.  side.  A  set  of  2  X  6-in.  braces  was  placed  between  these 
posts  at  every  3  ft.  of  elevation.  In  placing  the  forms  two  sets  of  false 
timbering  were  removed,  giving  room  for  a  set  of  form  posts  12  ft.  long. 
These  were  put  in,  plumbed  and  braced  and  the  2-in.  plank  nailed  to  them 
a  foot  or  so  in  advance  of  the  concrete  as  it  was  filled  in.  When  the  form 
was  full,  two  more  sets  of  timbering  were  removed  and  another  set  of 
form  posts  put  in  place,  so  repeating  the  operation  until  the  entire  section 
was  completed.  Forms  were  left  in  place  in  each  section  until  the  entire 


106  DETAILS  OF  PRACTICAL  MINING 

section  was  completed,  then  taken  out,  beginning  at  the  top,  and  cleaned 
for  use  in  the  next  section. 

The  specifications  called  for  forms  behind  the  concrete  and  back  filling 
behind  these  forms  for  all  cavities  of  too  great  size  to  be  filled  with  con- 
crete, but  as  the  work  proceeded  the  contractors  realized  it  would  be 
cheaper  and  more  efficient  to  build  rubble  walls  instead  of  back  forms, 
filling  in  all  back  space  with  broken  rock  and  boulders  -of  sizes  easily 
handled.  When  this  rubble  work  was  used  the  thickness  of  concrete 
walls  was  increased  to  as  much  as  18  in.  in  some  instances  and  reinforced, 
the  thickness  of  the  wall  and  the  quantity  of  reinforcement  depending 
upon  the  vertical  height  of  back  filling,  which  in  one  instance  was  about 
65ft. 

The  mixture  to  be  poured  between  the  rubble  walls  and  the  form  was 
mixed  dry  enough  that  no  water  would  appear  upon  the  surface  after 
being  well  worked  in  a  plastic  mass  that  would  run  slowly  down  a  slope 
of  20°.  This  dry  mixture  went  through  the  pipe  as  readily  as  if  wetter. 
Had  the  thinner  mixture  been  used  the  water  would  have  separated  from 
the  sand  and  rock,  taking  the  cement  with  it  and  leaving  a  lean  concrete 
behind. 

The  long  walls  of  the  lining  were  given  a  minimum  thickness  of  10 
in.  and  the  short  walls  and  center  partition,  8  in.  Where  the  rock  walls 
were  very  irregular,  forming  large  cavities,  large  rocks  brought  down  on 
the  cages  were  thrown  into  the  concrete.  The  center  partition  was  rein- 
forced every  18  in.  vertically  with  mine  rails  laid  across  the  shaft  in  the 
center  of  the  wall.  The  end  and  side  walls  were  thus  reinforced  only  at 
points  where  the  ground  was  bad  and  at  stations.  Bolts  were  imbedded 
in  the  concrete  at  regular  intervals  for  fastening  the  guides.  Old  water 
pipes  were  cut  into  short  lengths  and  placed  in  the  concrete  for  weep 
holes  through  the  walls.  A  set  of  four  of  these  was  placed  every  5  ft. 
The  best  time  for  placing  these  pipes  was  at  the  end  of  a  run  of  concrete, 
when  they  could  be  placed  and  pushed  down  until  covered  with  concrete, 
without  being  filled. 

The  concrete  was  a  1:3:6  mixture  of  portland  cement,  quartz  sand, 
and  crushed  limestone  from  J^-in.  to  1-in.  mesh.  About  2300  cu.  yd. 
of  concrete  and  750  cu.  yd.  of  large  rock  were  used.  About  25  men  were 
employed  on  the  job,  working  two  shifts.  The  total  time  consumed 
was  eight  months,  of  which  the  first  month  was  spent  in  rigging  up  the 
surface  plant,  etc.,  and  most  of  the  rest  of  the  time  in  cleaning  down  the 
walls  and  putting  in  temporary  timbering  preparatory  to  concreting. 
In  addition,  the  lower  110  ft.  of  the  shaft  consisting  of  a  raise  driven  to 
one-compartment  size  had  to  be  enlarged  to  full  size.  The  actual  work 
of  concreting  was  done  in  JOO  days,  or  about  40  per  cent,  of  the  total  time 
consumed.  Ordinarily,  one  12-ft.  section  of  concrete  per  day  was  put 


SHAFTS  AND  RAISES  107 

in,  but  in  bad  ground  a  6-ft.  form  would  be  used.  The  maximum  day's 
work  was  22  ft.  The  two  compartments  are  5  ft.  by  7  ft.  2  in.  inside  the 
finishing  lining.  The  shaft  is  used  only  for  ventilation  and  for  hoisting 
and  lowering  men  working  in  the  east  end  of  the  mine. 

It  is  most  interesting  to  note  that  the  area  of  the  compartments  is 
over  60  per  cent,  greater  than  the  area  of  the  old,  timbered  compartments, 
which  were  4  ft.  by  5  ft.  6  in.  showing  that  with  a  given  area  of  ground 
broken  a  much  larger  shaft  area  may  be  obtained  with  a  concrete  than  with 
a  timber  lining.  The  contractors  received  $30,000  for  their  work,  or  $28 
per  foot. 

Concreting  the  Junction  Shaft  (By  Robert  H.  Dickson). — The 
Calumet  &  Arizona  Mining  Co.,  of  Bisbee,  Ariz.,  replaced  the  timbers  of 
its  Junction  shaft  with  concrete.  The  new  shaft,  27  ft.  3  in.  long  and  6  ft. 
wide,  was  concreted  to  the  surface  from  a  point  1535  ft.  below  in  8 
months  and  24  days.  Except  at  the  stations,  standard  sets  of  forms, 
which  could  easily  be  set  up  and  taken  apart,  were  used.  The  materials 
used  for  the  concrete  were  stored  in  overhead  bins,  from  which  they 
could  easily  be  fed  to  the  concrete  mixer,  Fig.  89.  The  1:3:5  mixture 
was  dropped  through  an  iron  pipe  to  that  part  of  the  shaft  where  it  was  to 
be  placed.  Steel  reinforcement  of  %-in.  rods  with  a  tensile  strength  of 
50,000  Ib.  per  square  inch,  was  used  in  the  curtain  walls  which  separated 
the  shaft  compartments;  in  the  columns  required  at  stations;  and  in  the 
shaft  walls,  where  back-filling  was  necessary. 

The  shaft  as  concreted  is  18  in.  wider  and  13  in.  longer  than  the  old 
shaft,  the  dimensions  of  all  the  compartments  being  increased.  The 
relative  size  of  the  old  and  new  shafts  is  shown  in  Fig.  90,  compartments 
1  and  5  being  pipe  compartments;  3  and  4,  the  main  hoisting  compart- 
ments; and  2,  the  dinky  cage  compartment.  Concrete  curtains  separate 
the  compartments,  except  that  between  Nos.  1  and  2  wood  is  used. 

In  the  walls,  the  concrete  was  placed  usually  to  fill  all  the  space 
between  the  forms  and  the  solid  rock.  Where  the  rock  opened  out  so  as 
to  make  necessary  a  wall  over  2  ft.  thick,  a  dry  wall  was  built  of  rock  and 
loose  rock  was  thrown  in  behind.  The  concrete  wall  was  never  less  than 
8  in.  thick,  except  where  a  rock  of  less  than  4  sq.  ft.  in  area  projected  no 
closer  to  the  form  than  4  in.  At  10-ft.  intervals,  2  X  5-ft.  windows  or 
air  vents  were  left  in  the  curtain  walls  to  obviate  the  suction  which  would 
be  created  by  the  cage  moving  in  so  long  a  tube.  Scaffolding  boxes  were 
left  every  5  ft.  in  the  pipe  compartments,  so  as  to  permit  staging  to  be 
erected  at  any  part  of  the  shaft.  I-beams  for  carrying  the  pipes  were 
set  every  20  ft.,  and  others  for  electric  cables  every  40  ft.  from  the  1510 
level  to  the  770,  and  every  100  ft.  from  the  770  to  the  surface.  The 
reinforcement  in  the  curtains  was  placed  horizontally  about  every  2% 
ft.,  one  rod  being  close  to  one  side  of  the  curtain,  the  next  to  the  "other. 


108 


DETAILS  OF  PRACTICAL  MINING 


U //'-3"— H 


I  Overhead  Storage 
t  5ins,  Rock,  Sand  and 
{Cement 


Ring  for  hand/ing 
-forms  with  hoisting 
cable 


Wndow/effin 
xurtain  wall 

FIG.    89. VERTICAL  SECTION,  JUNCTION  SHAFT,  SHOWING  MANNER  OF  OPERATION. 


SHAFTS  AND  RAISES 


109 


The   ends   of  the   rods  were   bent   at  45°  to  give  a  grip  on  the  side 
walls. 

The  forms  consisted  of  sections  5  ft.  high.     Three  complete  sets  of 


Detail  of  Curtain  Wall, Guides 
And  Guide  Dolts 


<  inside  of  old  shaft  timber 


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Section  5-B 


Section  A~A 


FIG.    90. SHAFT  SECTIONS  SHOWING  RELATIONS  OF  CONCRETE  AND  OLD  TIMBER. 

forms  were  used,  the  lowest  being  taken  out  as  needed  above.  They 
were  of  timber  dressed  to  1%  in.,  and  fastened  together  with  M-in. 
plates.  Before  being  put  together,  the  boards  were  thoroughly  soaked 


110 


DETAILS  OF  PRACTICAL  MINING 


in  water  so  as  to  be  in  the  same  condition  while  making,  as  they  would  be 
while  in  use.  The  forms  consist  of  four  pieces  for  each  compartment, 
or  more,  in  the  case  of  those  compartments  where  pipes  in  the  shaft  did 
not  allow  the  handling  of  large  pieces.  In  general  braces  of  2  X  3  X  J£- 
in.  angles,  were  used  across  the  compartments  between  the  sections  of 
the  forms,  to  stay  them  against  bending  and  movement. 

In  No.  4  compartment,  typical  of  the  others,  the  forms  consisted  of  two 
sides,  marked  A  in  Fig.  91  and  the  two  ends,  B.  The  boards  of  each  piece 
were  fastened  together  with  4-in.  channel  at  the  center  and  a  J^-in. 
plate  at  each  end.  Horizontal  angles  at  the  top  reinforced  the  forms 
against  buckling  and  also  supported  the  boards  of  the  working  floors. 
As  the  angles  were  below  the  top  of  the  form,  these  boards  did  not  project 
over  the  curtain  walls  and  were  held  in  place.  All  four  corners  of  the 


4-2^- — » 


Section's" 


fillpttfyVJ^tg 
Section'*" 
FIG.    91. ARRANGEMENT  OF  THE    FORMS  IN  THE  SHAFT  AND  DETAILS  OF  TWO  SECTIONS. 


set  were  beveled  to  allow  easy  removal  from  the  concrete.  Each  piece 
was  provided  with  a  ring  for  easier  handling.  The  four  pieces  were 
held  together  by  a  6-in.  angle  iron  at  each  corner  of  the  compartment. 
In  compartment  No.  1,  the  end  was  made  in  two  pieces  so  as  to  allow  it  to 
be  slipped  out  from  behind  the  pipes.  Compartments  No.  1  and  2  are 
really  one  large  compartment,  divided  by  a  timber  partition.  Timber 
was  used  instead  of  concrete  in  order  that  the  two  compartments  might 
be  thrown  into  one,  if  desired  later.  In  several  cases,  as  in  No.  1  and  2 
compartments,  a  long  side  consisted  of  two  pieces  fastened  together  by 
bolts  and  keys,  as  shown.  The  end  of  No.  5  compartment  consisted  of 
loose  12-in.  boards  because  the  pipes  at  that  end  of  the  shaft  would  not 
permit  any  other  arrangement.  A  bolt  through  the  curtain  wall  held 
the  forms  of  each  compartment  to  those  of  the  adjoining. 


SHAFTS  AND  RAISES  111 

Concrete  columns  16  in.  square  took  the  place  of  walls  at  the  stations 
where  openings  had  to  be  left  in  the  sides  of  the  shaft.  Curtain  walls 
extended  between  the  two  opposite  columns,  as  in  the  case  of  the  walls 
above.  The  columns  were  reinforced  with  %-in.  steel  rods  tied  with  wire. 
At  the  1400  level  an  ore  pocket  17  X  17  X  28  ft.  was  concreted.  Forms 
were  made  underground  as  needed  for  the  station  columns  and  this 
pocket,  and  the  concrete  was  poured  into  these  in  the  same  manner  as 
with  other  parts  of  the  shaft. 

A  4-in.  conveying  pipe  extended  the  whole  length  of  the  shaft  and 
terminated  4  in.  above  the  top  of  the  receiving  bucket,  an  ordinary  sinking 
bucket  with  a  spout  attached.  Concrete  from  the  mixer  was  dropped 
through  this  pipe  into  the  bucket,  and  thence  poured  through  chutes  so 
as  to  fill  all  the  space  between  the  forms  and  the  rock  walls.  The  cycle  of 
operations  involved  concreting,  removing  timber,  pulling  forms  from  below 
and  setting  them  up  above.  After  a  set  was  filled  with  concrete,  a  board 
floor  was  placed  across  the  top  of  the  last  set  of  forms  and  upon  this  the 
men  worked  in  removing  the  shaft  timber. 

Only  enough  timber  was  taken  out  at  a  time  to  permit  concreting. 
One  man  split  the  nuts  of  the  1%-in.  hanging  bolts  of  the  set  above  with 
a  compressed-air  cutter,  while  the  concrete  was  being  poured.  At  first, 
several  of  the  dividers  were  chopped  in  two  and  pulled  out  of  place  by  a 
chain  fastened  below  the  hoisting  cage.  This  loosened  the  wall  plates, 
which  were  in  two  pieces;  thus  the  posts  could  be  removed.  Then  by 
fastening  the  chain  to  the  wall  plates,  they  were  pulled  from  their  posi- 
tion. As  each  piece  of  timber  was  dislodged,  it  was  placed  on  the  cage. 
The  removal  of  the  timbers  often  dislodged  some  loose  rock.  In  the  case 
of  bad  ground,  before  a  portion  of  the  set  was  removed  or  immediately 
after,  long  pieces  of  lagging  or  stringers  were  placed  up  against  the  walls 
so  that  their  upper  ends  could  be  blocked  behind  the  last  set  of  timbers  in 
place,  if  possible,  and  their  lower  ends  held  in  place  against  the  wall  by 
stulls  or  braces  extending  across  the  shaft.  Often  the  stringer  or  lagging 
was  held  in  place  by  several  stulls.  Except  at  stations,  the  open  ground 
above  a  set  to  be  concreted  never  exceeded  10  ft.  As  concreting  pro- 
ceeded, these  stringers  or  lagging  pieces  were  removed,  if  possible. 

After  removing  the  timbers,  the  temporary  floor  was  taken  up  and 
the  forms  were  pulled  from  the  lowest  set  in  place,  set  up,  and  blocked. 
Two  bulkheads  were  always  kept  below  the  men,  one  5  ft.  below  the  lowest 
set  of  forms  and  one  30  ft.  below  this.  In  pulling  forms,  two  men  loosened 
them  below  while  two  above  set  them  in  place.  The  only  tools  required 
were  a  wrench  and  short  bar.  Beside  the  three  sets  of  forms,  used  in  the 
shaft,  two  other  sets  were  kept  to  supply  repair  parts.  As  stated,  the 
four  pieces  of  form  for  each  compartment  were  held  together  by  bolting 
to  angle  irons  at  the  four  corners  of  the  compartment.  In  the  end  pieces, 


112 


DETAILS  OF  PRACTICAL  MINING 


the  nuts  were  contained  in  the  form,  Fig.  92,  so  that  by  unscrewing  the 
bolt,  leaving  the  nut  in  the  form,  the  corner  angles  could  be  speedily 
removed  from  the  keyed  bolt  of  the  side  pieces.  The  ends  of  the  angles 
had  one  flange  turned  over  and  welded.  After  taking  out  the  corner 
angles  from  below,  they  were  taken  to  a  point  above  the  last  set  of  forms 
in  place  and  were  fastened  to  the  corner  angles  of  this  set  by  means  of 
keys  and  bolts  through  holes  in  the  turned-over  ends.  Then  the  sides 
were  pried  off  from  the  walls  below  and  fastened  to  a  chain  suspended 
from  the  hoisting  cage,  lifted,  dropped  into  place  and  fastened  again  to 
the  respective  corner  angles.  The  end  pieces  were  similarly  handled. 

After  setting  up,  the  forms  were  leveled  and  blocked  in  place.  A 
line  was  stretched  across  the  shaft  between  two  plumb  lines,  and  the  upper 
edge  of  one  side  set  of  forms  was  blocked  out  from  the  rock  wall  so  that  it 
came  a  certain  distance  from  this  line,  and  similarly  with  one  end.  The 
lower  edge  of  the  set  was  held  in  position  by  fastening  to  the  set  below. 


Detail  of  Bolt  and 
Pins  through  Corner 
Angles  ^-' 


Detail  of 
Eye-bolt 
and  Ring 


Detail 

of 

„         Handle 
k/tiv        on 

Center  Angles 


FIG.    92. DETAILS  OF  SOME  OF  THE  FORM  FITTINGS. 

The  forms  were  carefully  leveled  by  means  of  a  straight-edge.  Small 
iron  wedges  were  placed  under  the  corners  of  the  forms  to  level  them  up, 
if  necessary.  Window  and  staging  boxes  were  placed  in  the  forms  as 
required. 

The  bucket  was  usually  hung  in  No.  2  compartment,  the  bottom  3  to 
4  ft.  above  the  top  of  the  set.  From  the  spout  the  concrete  was  conveyed 
to  the  point  of  deposit  through  chutes  which  telescoped  like  coal  chutes 
used  in  cities.  The  bottom  of  the  last  set  of  timbers  was  usually  2  or 
3  ft.  above  the  top  of  the  form.  In  dropping,  the  concrete  was  churned 
in  the  bucket  and  mixed  more  thoroughly  than  would  be  possible  in  the 
mixer.  The  concrete  was  tamped  into  place  behind  the  forms. 

Three  shifts,  each  of  eight  men  and  a  shift  boss,  made  up  the  shaft 
crew.  Each  shift  completed  as  much  of  a  cycle  as  it  could  and  the  next 
shift  started  where  the  preceding  shift  left  off.  The  time  required  to 
remove  timber,  pull  forms  and  concrete  varied  exceedingly  under  the 


SHAFTS  AND  RAISES 


113 


changing  conditions,  such  as  the  experience  of  the  men,  character  of  the 
ground,  etc  When  first  started,  the  work  required  as  much  as  two  shifts 
to  pull  forms,  while  later  on  the  average  time  was  5  hr.  During  the 
months  from  February  to  June,  it  required  an  average  of  about  20  hr.  to 
complete  the  cycle,  the  time  being  distributed  approximately  as  'follows : 
Removing  shaft  timbers,  5  hr.;  removing  waste  or  back  filling,  4  hr.; 
pulling  forms,  lining  and  blocking,  8  hr. ;  concreting,  3  hr.  For  the  upper 
450  ft.,  the  average  time  required  for  a  cycle  was  12j/£  hr.  with  an  approxi- 
mate distribution  of  time  as  follows:  Removing  timber,  2  hr.;  drilling 
and  shoveling,  4  hr. ;  pulling  forms,  lining  and  blocking  5  hr. ;  concreting, 
13^  hr.  For  this  instance,  the  walls  had  to  be  blasted  all  around  an 
average  of  8  in.,  making  about  25  cars  per  5  ft.  of  shaft.  The  actual  con- 
creting was  finished  Aug.  24,  1913. 

COST  SHEET  PER  FOOT  AND  PER  CUBIC  YARD  FROM  DEC.,  1912,  TO  AUG.  24,   1913 


1912, 
Dec. 

1913, 
Jan. 

Feb. 

Mar. 

Apr. 

May 

June 

July 

Aug. 

Yardage 

444  8 

900  3 

933  3 

1096  5 

1120  2 

1093  8 

931  5 

1000  2 

853  5 

Footage 

60 

140 

170 

185 

180 

200 

170 

235 

196 

Alteration  in  piping,  per  ft. 
Alteration  in  transmission 
lines,  per  ft 

$7.84 
0  74 

$4.42 
1  37 

$4.09 
0  58 

$3.44 
1   14 

$5.45 
2  36 

$3.87 
1   16 

$4.42 
0  54 

$1.94 
0  57 

$2.35 
0  98 

Removing   shaft   timber, 
per  ft 

19  40 

9  52 

6  66 

7  66 

9  27 

8  77 

7  08 

4  27 

3  87 

Waste  and  filling,  per  ft.  . 
Guides,  per  ft  
Hoisting,  per  ft  
(1)   Repairs   to   concrete 
pipe,  per  ft 

4.37 
0.14 
29.26 

3.88 
0.32 
12.15 

2.57 
2.35 
10.42 

4.09 
1.49 
10.37 

0  07 

4.41 
0.00 
9.96 

0  10 

4.68 
2.74 
9.78 

0  15^ 

10.75 
5.33 
o20.37 

0  12}^ 

7.11 
6.57 
6.25 

0  01 

12.06 
6.07 
7.36 

0  00 

(1)  Repairs    to    concrete 
pipe,  per  yd  

0.01 

0.017 

0  03 

0.03 

0  00 

0  00 

(2)  Forms,  per  ft  
(2)  Forms,  per  yd  

3.24 
.    0.44 

6.29 
0.98 

4.72 
0.86 

4.05 
0.68 

2.93^ 
0.38 

2.15 
0  39 

2.25 
0  30 

1.60 
0  38 

1.85 
0  43 

(3)  Cost  of  concrete  ma- 
terials, per  ft 

53  83 

43  52 

26  00 

30  31 

21  33 

23  68 

24  93 

18  50 

19  66 

(3)  Cost  of  concrete  ma- 
terials, per  yd 

7  26 

6  77 

4  73 

5  11 

3  43 

4  33 

4  55 

4  35 

4  53 

(4)   Moving  forms,  per  ft.. 
(4)   Moving  forms,  per  yd. 
(5)  Distributing  concrete, 
per  ft.   . 

27.17 
3.73 

9  20 

16.37 
2.55 

6  64 

11.63 
2.12 

4  06 

10.18 
1.72 

3  17 

8.93 
1.43J4 

2  77 

8.57 
1.57 

2  25 

8.20 
1.50 

2  73 

7.11 
1.67 

1  90 

7.00 
1.65 

2  50 

(5)  Distributing  concrete, 
per  yd.  .  . 

1   24 

0  92 

0  66!£ 

0  53 

0  44  J4 

0  41 

0  50 

0  45 

0  58 

Concrete  totals  1-2-3-4, 
per  ft.  . 

93  44 

72  82 

46  41 

47  78 

36  07 

36  80 

38  23 

29  12 

31  01 

Concrete  totals  1-2-3-4, 
per  yd 

12  67 

11  22 

8  38 

8  05 

5  72 

6  73 

6  88 

6  85 

7  19 

Supervision,  per  ft  
Supervision,  per  yd 

615.65 
2   11 

66.81 
1  06 

1.49 
0  27 

1.39 
0  24 

1.39 
0  24 

1.30 
0  14 

1.50 
0  27 

1.00 
0  24 

1.00 
0  23 

Miscellaneous,  per  ft  
Total,  per  ft  

2.08 
172.92 

0.67 
110.96 

0.47 
75.04 

1.45 
78.81 

0.52 
69.43 

0.84 
69.94 

1.69 
89.92 

0.73 
57.56 

0.62 
65.32 

Total  yardage,  8374.1;  total  footage,  1536. 
a  Includes  cost  of  new  hoist  rope. 

6  The  shift  bosses  during  Dec.  and  Jan.  were  carried  under  "supervision." 
8 


114  ,  DETAILS  OF  PRACTICAL  MINING 

The  guides  were  bolted  to  the  curtain  walls.  A  short  length  of  pipe 
was  set  in  the  curtain  wall  while  concreting,  with  wooden  blocks  at  its 
ends.  When  setting  the  guides,  the  blocks  were  removed,  the  guide 
bolt  inserted  and  held  tight  to  the  pipe  by  nuts  which  were  screwed  on  to 
occupy  the  cavities  left  by  the  blocks.  The  guides  were  placed  over  the 
bolts  and  held  by  nuts  in  recesses.  The  guides  were  set  from  a  "go- 
devil,"  a  box  as  long  as  a  guide,  of  a  cross-section  to  fit  the  compartment, 
the  four  corners  formed  of  four  long  stringers  held  together  by  crosspieces 
and  tie  rods.  On  the  crosspieces  were  laid  floors,  so  as  to  form  three 
decks  on  which  the  men  worked.  In  this  way  three  men  at  a  time  could 
bolt  on  a  guide,  one  on  each  deck. 

In  the  cost  table,  waste  and  filling  include  the  labor  and  supplies  used 
in  enlarging  the  shaft,  the  removing  of  the  waste  dislodged  while  tear- 
ing out  the  old  timbering  and  the  labor  and  supplies  used  in  refilling 
caves  in  the  shaft  caused  by  removing  timber.  Concrete  cost  includes 
the  cost  of  quarrying  and  crushing  the  rock,  the  freight,  sand,  cement 
and  supplies,  the  mixing  and  storing  of  the  concrete,  and  the  cost  of 
reinforcement. 

Rectangular  Concrete  Shaft  Lining  (Coal  Age). — A  shallow  concrete- 
lined  shaft  sunk  by  the  Bunsen  Coal  Co.,  of  Danville,  111.,  is  illustrated 
in  Figs.  93  and  94. 

The  thickness  of  the  walls  for  89  ft.  down  from  the  collar  is  18  in., 
and  thence  to  the  bottom  at  225  ft.,  12  in.  They  are  of  plain  concrete 
except  the  corners,  which  are  reinforced  vertically,  each  with  two  lines 
of  %-in.  by  16-ft.  twisted  steel  bars,  back  of  which  are  placed  %-in.  by 
6-ft.  bars  laid  horizontally  and  spaced  every  2  ft.  for  the  entire  depth  of 
the  shaft.  The  dividers  are  all  10-in.  I-beams  weighing  35  Ib.  per  foot. 

The  forms  were  composed  of  1J^  X  10-in.  tongue-and-groove  yellow- 
pine  boards,  surfaced  on  both  sides,  and  cut  into  lengths  making  the 
section  2%  ft.  high.  Nailing  strips  1J4  X  12  in.  extended  around  the 
top  and  lJ/£  X  4-in.  pieces  at  the  bottom  formed  cleats  for  the  several 
units  and  held  the  matched  boards  securely  in  place.  The  top  piece 
extended  a  distance  of  1  in.  above  the  top  of  the  form  on  the  inside 
for  the  reception  of  the  next  form  section.  For  stiffening  the  forms  and 
supporting  the  concrete  until  it  should  set,  a  steel  frame  consisting  of 
4  X  4  X  3^-in.  angles  was  placed  midway  of  each  section  and  attached  to 
the  form  boards  by  means  of  %-in.  bolts  spaced  13  in.  center  to  center 
around  the  entire  section.  The  steel  framework  was  stiffened  at  the 
corners  with  4  X  4  X  J^~m-  angle  bracing;  while  %-in.  splice  and  gusset 
plates  were  used  for  bolting  together  the  several  units  composing  the 
frame.  To  insure  easy  removal  of  the  forms  and  to  increase  the  thick- 
ness of  the  walls,  the  corner  pieces  were  cut  on  a  45°  angle  with  a  5-in. 
bevel  face.  The  vertical  edges  of  each  unit,  including  the  forms  and 


SHAFTS  AND  RAISES 


115 


angle  frames,  were  also  cut  on  a  45°  bevel,  while  6  X  10-in.  pockets  were 
made  in  the  top  of  every  other  form  for  the  reception  of  the  10-in.  I- 
beam  dividers  which  are  spaced  vertically  5  ft.  center  to  center.  The 
completed  2^-ft.  section,  including  the  steel  frame,  weighed  2080  lb., 
and  the  heaviest  unit  400  lb. 

No  concrete  was  poured  until  the  bottom  of  the  shaft  was  reached. 
A  temporary  lining  was  used  in  sinking.  The  8  X  10-in.  dividers 
supporting  the  temporary  lining  were  removed  as  the  concrete  lining 


Section  A-A 

FIG.    93. PLAN  AND  SECTION  OF  CONCRETE  LINING. 

advanced ;  these  were  replaced  after  each  form  was  in  position  with  4  X 
6-in.  temporary  supports  for  the  forms  until  the  concrete  had  set.  Both 
lines  of  4  X  6-in.  temporary  support  were  carried  on  1%  X  4  X  10-in. 
blocks  attached  to  1J^  X  10-in.  vertical  wall  plates  cut  in  5-ft.  lengths. 
These  plates  extended  back  of  the  forms.  Four  1J^  X  2J/£  X  10-in. 
blocks  attached  to  the  back  of  the  wall  plates  cleared  the  steel  angles  on 
the  forms  and  made  a  substantial  support. 

The  concrete  yardage  per  vertical  foot  for  12-in.  lining  walls  was 


116 


DETAILS  OF  PRACTICAL  MINING 


2.5  cu.  yd.,  and  3.8  cu.  yd.  for  walls  having  a  thickness  of  18  in.  All  of 
the  concrete  was  composed  of  one  part  cement  and  five  parts  of  clean 
river  gravel.  Concreting  started  Aug.  7,  1914,  and  the  collar  was 
reached  Sept.  8.  The  entire  work  done  in  connection  with  the  concreting 
of  the  shaft-lining  walls  occupied  four  and  one-half  weeks,  giving  an 
average  of  50  ft.  per  week. 


JT 


Ang/es 
af/  *!* 


u 


- &//*<• ;-- 

Plan  Showing  Forms  Assembled 


„„.-..> 
•> 


— +,%  Holes,  l5HCtoC.~6-3"~ - 


Center   Section  E 
PIG.    94. STEEL  FRAME  USED  FOR  STIFFENING  FORMS. 


Raising  and  Enlarging  Negaunee  No.  3  Shaft  (Lake  Superior  Mining 
Institute). — The  No.  3  shaft  at  the  Negaunee  mine,  Negaunee,  Mich., 
was  started  by  sinking  a  test  pit  to  solid  rock  through  68  ft.  of  sand  and 
hard  pan.  As  no  water  or  quicksand  was  encountered,  the  main  drift 
was  driven  from  the  bottom  level  of  the  old  workings,  806  ft.  below 
the  surface,  to  the  location  of  the  new  shaft.  A  raise  was  then  com- 
menced, to  connect  with  the  bottom  of  the  test  pit. 

The  general  arrangements  at  the  level  are  shown  at  2,  in  Fig.  95.  The 
cribbed  compartment  was  divided  in  the  center  by  2-in.  planks  forming 
two  compartments,  one  for  pipes  and  ladder,  and  the  other  for  a  small 
bucket  for  tools  and  cribbing.  In  3  is  shown  the  method  of  supporting 
the  cribbing,  and  the  arrangement  of  the  chutes.  Below  the  dirt  com- 
partment a  bench  of  solid  rock,  on  the  same  angle  as  the  lip  of  the  chute, 
served  as  a  permanent  indestructible  bottom.  The  cribbing  was  ac- 
curately framed  from  6-  to  8-in.  round  tamarack  timber,  each  piece  faced 
on  one  side  to  maintain  dimensions  inside  the  compartments.  This 


SHAFTS  AND  RAISES 


117 


FIG..  95. NEGAUNEE  NO.  3,  RAISE  AND  SHAFT. 


118  DETAILS  OF  PRACTICAL  MINING 

greatly  aided  the  miners  in  building  up  the  cribbing  plumb  and  made 
rapid  hoisting  practicable. 

The  crew  was  composed  of  nine  miners,  three  on  each  8-hr,  shift. 
Stopers  were  used  for  drilling.  It  was  not  advantageous  to  blast  a 
deeper  cut  than  5  ft.  on  account  of  the  breaking  or  shifting  of  the 
cribbing.  The  best  results  were  obtained  by  the  round  illustrated  in  3. 
Before  blasting,  the  cribbed  compartments  were  covered  with  a  6-in. 
sollar,  one  small  hole  being  left  in  the  ladder-road  side  to  allow  a  man  to 
pass  through  after  blasting.  The  round  of  16  holes,  was  blasted  with 
fuse  in  three  sections  as  follows:  (1)  Holes  1  and  2;  (2)  3  to  9;  (3)  10  to 
16.  At  intervals  of  about  200  ft.,  small  drifts  about  8  ft.  long  were  driven 
from  the  ladder  compartment,  each  drift  protected  by  a  door.  A  con- 
nection was  made  with  the  air  pipe  to  prevent  the  possible  danger  of  the 
men  being  knocked  out  if,  for  any  reason,  the  fan  failed  to  work.  It 
would  have  consumed  too  much  time  for  the  men  to  go  to  the  very  bottom 
after  the  raise  reached  a  great  height.  Before  blasting  the  crew  would 
enter  these  small  drifts  and  suffered  no  discomfort  even  when  the  back 
was  not  over  30  ft.  above  them. 

A  small  " puffer"  was  placed  on  the  level  and  run  by  compressed  air. 
After  each  cut  was  blasted  and  the  loose  rock  in  the  back  well  trimmed, 
a  stout  pole  was  wedged  across  the  raise  as  close  to  the  back  as  possible. 
A  10-in.  sheave  was  then  hung  from  this  pole  so  that  the  rope  leading 
to  the  bucket  was  in  the  center  of  the  hoisting  compartment,  the  other 
end  passing  down  one  corner  of  the  compartment  to  an  angle  sheave  and 
thence  to  the  puffer.  Signals  were  given  through  a  speaking  tube,  of 
IJ^-in.  pipe,  extending  from  the  puffer  to  the  top  set  of  cribbing.  An  oil 
barrel,  reinforced  in  the  bottom  with  wood  and  on  the  sides  with  steel 
strips,  was  used  in  preference  to  an  iron  bucket.  On  account  of  its  depth 
tools  and  cribbing  could  be  hoisted  with  little  danger  of  their  falling  out. 
The  bulge  in  the  center  lessened  the  possibility  of  the  buckets  catching  in 
the  cribbing. 

On  the  level  at  a  short  distance  from  the  raise  a  fan  capable  of  ex- 
hausting 2040  cu.  ft.  per  minute  was  set  up;  10-in.  spiral-riveted  pipe  with 
flanged  joints  every  10  ft.  extended  from  the  fan  up  into  the  ladder  com- 
partment. The  upper  end  of  the  pipe  was  kept  as  close  to  the  last  set 
of  cribbing  as  possible.  The  discharge  pipe,  10  in.  in  diameter,  of  gal- 
vanized iron,  was  not  perfectly  tight  and  caused  some  trouble.  It 
extended  to  an  abandoned  part  of  the  mine,  where  the  foul  air  was  dis- 
charged behind  a  tight  door,  which  prevented  it  from  reentering  the 
main  drift  and  contaminating  the  pure  air  needed  in  the  raise.  After 
blasting,  the  fan  was  started  and  the  gases  sucked  out.  It  was  found  a 
great  advantage  to  run  a  piece  of  old  hose  above  the  sollar  and  discharge 
compressed  air  directly  after  blasting,  in  order  to  hasten  the  removal  of 


SHAFTS  AND  RAISES  119 

the  gases.  The  gases  were  all  removed  within  15  min.,  but  as  an  extra 
precaution  the  men  did  not  return  to  work  for  30  min.  It  was  not 
necessary  to  run  the  fan  except  while  blasting. 

On  Jan.  1,  1909,  the  top  of  the  raise  was  20  ft.  above  the  rail  in  the 
drift.  On  July  19,  1909,  a  hole  was  located  in  the  back  of  the  raise  to 
strike  the  center  of  the  test  pit,  the  size  of  which  was  2  X  3  ft.  The 
first  attempt  was  successful,  showing  that  the  raise  had  been  brought 
up  accurately.  The  total  distance  from  the  rail  to  the  bottom  of  the 
test  pit  is  738  ft. 

In  order  to  avoid  hanging  up  of  the  raise  while  stripping  to  full  shaft 
section  was  going  on,  it  was  decided  to  remove  all  the  timber  before  be- 
ginning stripping.  For  this  purpose  a  platform,  7  X  16  ft.,  was  made  of 
8-in.  round  tamarack  bolted  to  crosspieces  as  shown  in  4.  A  wire  rope 
was  attached  to  each  corner  so  that  the  platform  would  hang  at  65°  from 
the  horizontal.  It  was  hoisted  one  piece  at  a  time  and  bolted  together 
at  the  top  of  the  raise.  A  10-in.  sheave  was  hung  from  a  strong  timber 
at  the  back  of  the  raise;  the  platform  was  slung  from  this  by  a  J^-in.  rope 
as  shown,  the  other  end  of  the  rope  passing  through  a  slot  in  the  platform 
and  down  the  hoisting  compartment  to  a  small  puffer  on  the  level  below. 
The  platform  served  to  protect  the  men  from  any  possible  fall  of  rock, 
the  steep  angle  tending  to  prevent  breakage.  The  cribbing  timber  as 
removed  was  lowered  in  a  bucket  supported  by  a  sheave  attached  to  the 
platform.  The  platform  was  always  kept  at  the  proper  height  above  the 
workmen.  Pipe,  cribbing  and  plank  were  removed  from  the  raise  in  28 
days. 

A  circular  shaft  was  decided  upon,  17  ft.  in  diameter  and  with  a  1  J^-ft. 
wall,  as  shown  in  1.  The  raise  was  blasted  through  into  the  test  pit  and 
sand  was  milled  down  to  enlarge  the  surface  excavation  sufficiently  to 
permit  installing  concreting  equipment.  The  sand,  however,  packed  in 
the  raise  bottom  and  as  water  accumulated  came  out  in  rushes.  The 
rest  of  the  sand  was  therefore  hoisted  by  means  of  a  bucket  on  a  derrick. 
At  40  ft.  below  the  original  surface,  a  hexagonal  wooden  shaft,  24  ft. 
inside  diameter,  was  built.  The  sets  were  5  ft.  apart  with  3-in.  planks 
spiked  to  the  outside,  5Z>.  Alternate  planks  were  cut  5  ft.  6  in.  and  11  ft. 
in  length,  thus  tying  the  sets  together  and  developing  a  rigid  structure. 
This  shaft  was  allowed  to  drop  slowly  to  the  ledge  as  the  material  below 
was  excavated. 

A  track  was  run  at  the  surface  to  a  nearby  gravel  bed  and  bins,  water 
tank,  mixer  and  a  kibble  on  a  truck  installed  as  shown  in  5.  The  kibble 
could  be  pushed  to  the  center  of  the  shaft  and  lowered  on  the  hoisting 
rope  to  dump  into  the  forms.  A  crew  of  five  surface  men  handled  35  cu. 
yd.  in  an  8-hr,  shift,  sufficient  for  10  ft.  of  shaft  lining.  The  water  was 
heated  to  boiling  by  exhaust  steam  and  in  winter  the  gravel  was  also 


120  DETAILS  OF  PRACTICAL  MINING 

heated  by  steam  pipes  in  the  bin  bottom.  Cement  was  handled  down  a 
chute  kept  constantly  full  with  the  bags,  the  removal  of  one  from  below 
allowing  the  whole  row  to  slide  down. 

The  sides  of  the  raise  were  stripped  down  with  hand-hammer  machines, 
the  usual  round  being  18  holes,  16  ft.  deep,  blasted  with  delay-action 
electric  fuses.  As  great  a  depth  as  possible  was  stripped  at  a  time,  the 
distance  being  a  multiple  of  ten  and  varying  from  20  to  90  ft. 

The  concreting  forms  were  rings  5  ft.  high  and  17  ft.  in  diameter,  in 
four  sections.  After  a  section  was  stripped,  the  engineer  located  the 
bottom  of  the  lowest  form.  A  base  for  the  forms  was  made  around  the 
collar  of  the  raise  by  means  of  a  number  of  short  pieces  of  timber  properly 
leveled,  6A.  A  floor  B  was  made  of  2-in.  hardwood  planks,  7  ft.  long, 
sawed  to  a  radius  of  10  ft.,  the  radius  of  the  rock  section  of  the  shaft. 
Small  openings  next  the  rock  were  stopped  with  small  pieces  of  wood  to 
hold  the  concrete.  A  6-ft.  hole  remained  in  the  center  of  the  floor.  One 
of  the  floor  planks,  C,  was  laid  with  the  wide  end  in  to  make  removal 
easy.  The  first  form  lowered  was  of  special  shape  so  as  to  leave  the  con- 
crete bottom  edge  at  an  angle  of  45°,  5 A.  A  regular  form  was  lowered 
and  set  upon  this,  being  positioned  by  plumb  lines  from  above.  The 
steel  dividers  were  lowered,  positioned  by  plumbing  and  clamped  to  the 
forms.  They  thus  served  to  support  a  working  platform.  The  concrete 
distributing  trough  was  next  placed  in  position,  extending  from  the  shaft 
center  to  the  edge  of  the  forms,  with  a  drop  of  2  ft. 

The  kibble  was  lowered  with  J£  yd.  of  concrete  and  dumped  into  the 
trough  by  means  of  a  hook  on  a  rope,  caught  into  a  ring  on  the  kibble 
bottom.  Forms  for  another  section,  10  ft.  high,  were  next  put  into  place 
together  with  another  set  of  steel  members.  After  completing  the  con- 
creting of  the  15  ft.,  requiring  48  hr.,  the  floor  under  the  lowest  form  could 
be  removed,  together  with  the  lowest  set  of  forms,  for  use  higher  up.  The 
routine  was  for  the  morning  shift  to  concrete  10  ft.  of  shaft  one  day  and 
place  10  ft.  of  forms  the  next,  the  night  and  afternoon  shifts  stripping 
and  preparing  the  next  section.  The  size  of  the  crew  was  figured  so  that 
both  operations  proceeded  at  about  the  same  rate.  For  the  section  of 
shaft  between  the  rock  and  the  surface,  special  wooden  forms  were  used 
as  it  would  have  required  too  much  concrete  to  fill  the  space  between  the 
steel  forms  and  the  hexagonal  shaft.  These  were  rings  of  strap  iron  bent 
to  a  diameter  of  20  ft.  with  3-in.  hardwood  planks  wired  to  the  inside  of 
them. 

To  cover  the  raise  collar  during  stripping  a  12  X  12-ft.  platform,  5C, 
was  used;  this  had  wire  ropes  from  the  corners  to  a  central  ring  and  was 
hoisted  and  suspended  from  the  lowest  steel  sets  during  blasting. 

In  making  the  joint  between  two  sections  of  the  concrete,  the  top  of 
the  form  for  the  new  section  would  be  in  line  with  the  thin  edge  of  the 


SHAFTS  AND  RAISES  121 

45°  bottom  of  the  old  section.  A  collar  was  then  bolted  to  the  form,  its 
height  1H  ft-,  its  upper  edge  turned  toward  the  shaft  to  form  a  lip. 
Rich  concrete  was  rammed  in  between  the  ring  and  the  old  face ;  the  space 
was  not  filled  in  this  first  operation.  After  the  concrete  had  set,  the  collar 
was  taken  off,  all  leaks  between  the  old  and  the  new  faces  caulked  with 
oakum,  and  the  small  remaining  triangular  space  filled  with  rich  mortar. 
In  this  way  all  water  was  pretty  thoroughly  shut  off. 

Through  the  main  stretch  of  the  shaft,  from  the  ninth  level  to  the 
top  of  the  rock,  the  work  cost  per  foot  for  raising,  $18.68;  for  stripping, 
$17.33;  for  steel  dividers,  $10.06;  for  steel  forms,  $1.26;  for  temporary 
surface  structure  and  equipment,  $6.74;  for  concrete,  $17.22;  for  com- 
pressed air,  $1.00;  giving  a  total  cost  per  foot,  less  salvage,  of  $72.17. 
The  length  of  this  stretch  was  738  ft.  and  the  speed  of  stripping  and  lining 
was  64  ft.  per  month.  The  total  cost  of  the  work  between  the  rock  and 
the  surface  was  approximately  $5890  and  for  the  158  ft.  from  the  skip 
pit  to  the  ninth  level,  involving  winzes  and  special  work,  it  was  $17,840. 
The  cost  per  yard  of  the  concrete  was  $7.64;  the  average  thickness  of  the 
walls  was  16.2  in. 

Steel  and  Concrete  Lining  of  Palms  Shaft  (Lake  Superior  Mining 
Institute). — The  recently  sunk  Palms  shaft  of  the  Newport  Mining  Co. 
is  vertical,  lined  with  steel  and  concrete.  It  is  divided  into  five  compart- 
ments, as  shown  in  Fig.  96.  The  skip  compartments  are  4  ft.  10  in.  by 
6  ft.,  and  the  cage  compartment  is  6  ft.  2  in.  by  10  ft.  The  outside  dimen- 
sions of  the  shaft  are  10  ft.  10  in.  by  17  ft.  6  in.  The  17-ft.  6-in.  wall  plates, 
the  end  plates  and  the  two  dividers,  each  10  ft.  long,  are  5-in.,  18.7-lb. 
H-section  steel  members.  The  other  two  dividers  are  4  ft.  10  in.  long 
and  consist  of  4-in.,  13.6-lb.  H-sections.  The  eight  studdles  are  3  X  3  X 
Ji-in.  angle  irons.  Most  of  the  sets  are  spaced  8  ft.  center  to  center,  but 
in  heavy  ground  some  sets  are  spaced  6  ft.,  and  a  few  of  them  4  ft.  The 
wood  guides  are  5%  in.  by  7%  in.,  and  two  of  them,  as  shown,  are  strength- 
ened by  7-in.  channels.  Hoisting  was  done  with  two  26-cu.  ft.  buckets 
weighing  900  lb.,  operated  by  an  electric  hoist.  Another  single-drum 
electric  hoist  handled  a  light  cage  for  timbermen,  running  in  the  middle 
compartment  of  the  shaft.  The  shaft  passes  through  quartzite  for  part 
of  its  distance;  the  broken  quartzite  was  saved  and  crushed  for  concreting 
purposes. 

It  was  found  possible  when  the  rock  would  stand  for  14  ft.  below  the 
lowest  set,  to  rivet  the  steel  members  together  on  the  surface,  lower  the 
set  intact  and  swing  it  into  place.  Shoes  on  the  two  lower  corners  guided 
it  to  the  shaft.  Four  1-ton  duplex  chain  blocks  were  used  for  swinging 
it  into  position.  To  each  corner  of  the  set  was  fastened  a  J^-in.  sling 
chain  about  3  ft.  long,  with  a  5-in.  ring  on  one  end  and  a  3-in.  ring  on  the 
other,  to  which  the  hooks  of  the  chain  blocks  were  attached.  When  a 


122 


DETAILS  OF  PRACTICAL  MINING 


14-ft.  space  could  not  be  maintained,  the  sets  were  riveted  in  parts  and 
bolted  together  below.  When  the  rock  walls  were  more  than  8  or  9  in. 
from  the  sets,  4-in.  tie  timbers  were  placed  vertically  4  in.  outside  the 
sets  and  about  2  ft.  apart.  Between  the  steel  sets  and  these  timbers, 
4-in.  wood  blocks  12  in.  long  were  placed.  Outside  the  verticals,  1-in. 
rough  boards  were  set  horizontally  to  act  as  outside  forms  when  it  came 
time  to  pour  the  concrete  lining.  Between  the  boards  and  the  solid  rock, 
lagging  was  filled  in.  When  the  rock  was  less  than  8  or  9  in.  from  the  sets, 
4-in.  flat  timbers  were  placed  between  the  flanges  of  the  wall  plates  and 
end  plates,  and  lagging  was  placed  behind  these  up  to  the  rock.  This 
lagging  was  left  in  place  until  concreting  time,  when  it  was  removed  from 
the  shaft. 


FIG.    96. PLAN  OF  PALMS  SHAFT. 

During  the  process  of  sinking,  at  every  75-  to  100-ft.  point  two  or 
three  adjacent  sets  were  filled  in  solid  to  the  rock  with  concrete,  eliminat- 
ing the  necessity  of  bearers  set  in  hitches.  This  concrete  was  mixed  on 
the  surface  and  lowered  in  a  hopper,  from  the  bottom  of  which  a  flexible 
spout  extended.  The  hopper  is  shown  in  Fig.  97  and  the  spout  in  Fig.  98. 

When  a  depth  of  1207  ft.  was  attained,  it  was  thought  necessary  to 
complete  the  concreting,  because  of  the  approach  of  cold  weather.  This 
concreting  was  started  at  a  depth  of  1170  ft.  The  concrete  was  mixed 
on  the  surface  in  the  proportions  of  1:3:5  and  carried  through  a  launder 
to  a  4-in.  flanged  pipe  down  the  shaft,  which  telescoped  into  a  5-in.  branch, 
shown  in  Fig.  98.  The  branch  took  the  blow  of  the  concrete,  and  at  its 
bottom  it  was  connected  with  a  reverse  bend  having  its  lower  end  vertical. 
An  18-ft.  flexible  spout  fitted  over  this  directed  the  concrete  to  the  proper 
place  behind  the  form.  While  the  concreting  force  was  filling  one  set, 


SHAFTS  AND  RAISES 


123 


other  men  were  removing  the  blocking  from  the  set  above,  hanging  strands 
of  old  wire  rope  vertically  1  ft.  apart  and  horizontally  about  3  ft.  apart, 
to  be  used  for  reinforcement,  and  placing  the  ouside  forms.  For  an 
8-ft.  span,  2-in.  hardwood  planks  were  used,  and  for  the  4-ft.  and  6-ft. 
spans,  1^-in.  hardwood  planks.  The  planks  were  cut  on  a  bevel  at 
the  upper  end,  so  that  the  concrete  came  out  underneath  the  steel  set 
to  act  as  a  support.  At  the  bottom  end,  in  passing  into  the  outside 
flange  of  the  H-sections,  2-in.  strips  of  wood  about  12  in.  long  were  laid 
1  in.  apart  between  the  bottom  end  of  the  plank  and  the  inside  flange  of 
the  section.  When  these  strips  were  removed,  the  planks  were  easily 
taken  out.  The  corners  were  left  open  for  concreting,  so  that  a  solid 
column  of  concrete  was  obtained  in  each  corner  over  the  entire  depth  of 
shaft.  Furthermore,  where  lagging  and  timber  were  left  between  the 


PIG.    97. HOPPER  FOR  LOWERING  SMALL  LOTS  OF  CONCRETE. 

concrete  and  the  rock,  openings  for  the  concrete  were  left  directly  back 
of  the  wall  plates  and  end  plates  to  the  solid  rock,  so  that  in  all  cases  the 
concrete  extended  from  the  steel  set  to  the  rock.  A  6  X  8  X  12-in. 
block  was  laid  in  the  concrete  midway  between  the  8-ft.  sets,  to  serve  as  a 
support  for  the  two  end  guides. 

Nine  miners  and  one  foreman  per  shift  did  the  drilling,  blasting  and 
mucking  and  assisted  the  timbermen  in  placing  the  sets,  concrete  bearers 
and  12-in.  ventilating  pipes.  Three  timbermen  per  shift,  with  two  fore- 
men for  the  24  hr.,  lagged  the  sets,  put  in  the  guides,  extended  the  air 
lines,  placed  the  ladders  and  substituted  for  absent  miners.  There  were, 
furthermore,  for  each  24  hr.,  four  engineers,  two  top-landers,  two  men  to 
handle  rock,  etc.,  and  two  blacksmiths.  The  concreting  required  the 
10  miners  for  removing  lagging,  placing  reinforcement  and  placing  plank 
forms.  The  four  timbermen  attended  to  the  distribution  of  the  concrete 


124 


DETAILS  OF  PRACTICAL  MINING 


FIG.    98. VERTICAL    SECTION    OF    SHAFT,    SHOWING    SETS    AND    FORMS    AND 

FLEXIBLE   SPOUT. 


SHAFTS  AND  RAISES  125 

to  the  forms.  On  the  surface,  three  men  wheeled  rock  to  the  mixer,  two 
men  the  sand  and  cement,  one  poured  water  and  attended  to  the  secur- 
ing of  the  proper  mixture,  one  discharged  the  mixer,  one  looked  after  the 
launder  from  the  mixer  to  the  4-in.  pipe,  and  two  men 'worked  the 
concrete  down  the  4-in.  pipe.  All  the  men  worked  8-hr,  shifts  on  the 
concreting. 

The  speed  of  sinking  the  shaft,  including  the  placing  of  steel  sets  and 
lagging,  occasional  concreting,  etc.,  averaged  from  4  to  4.56  ft.  per  day 
during  several  months.  For  the  last  three  weeks  in  August,  1913,  it 
averaged  5  ft.  per  day.  The  speed  of  final  concreting  was  from  35  to 
48  ft.  per  day.  For  the  total  distance  concreted,  78  gondolas  of  sand 
and  15,695  sacks,  or  21  carloads,  of  cement  were  required. 

Unit  Sets  of  Reinforced  Concrete  (From  a  paper  by  E.  R.  Jones 
before  the  Michigan  College  of  Mines  Club). — Concrete  members  molded 
separately  on  the  surface  were  made  for  the  No.  3  and  No.  4  shafts  of 
the  Ahmeek  Mining  Co.  The  shafts  are  sunk  at  an  angle  of  80°  and 
are  3-compartment  shafts,  two  skipways  and  one  manway.  The  out- 
side dimensions  of  the  compartments  are:  skipways,  7  ft.  6  in.  high,  by 
6  ft.  10  in.  wide;  manway,  7  ft.  6  in.  high,  3  ft.  wide,  with  the  end  plates 
and  dividers  making  the  greatest  span  of  7  ft.  6  in.  Offsets  were  molded 
in  all  plates  5  in.  from  the  inside  face  to  accommodate  lining  slabs.  Also, 
holes  were  cored  for  hanging  and  bracket  bolts.  The  wall  plates,  end 
plates  and  studdles  had  a  cross-section  of  80  sq.  in.,  the  dividers  81  sq. 
in.  The  percentages  of  reinforcement  were  approximately  as  follows: 
Wall  and  end  plates  and  dividers,  5  per  cent.;  studdles,  3  per  cent. 

The  materials  finally  selected  were  portland  cement,  conglomerate 
sand,  and  trap  rock  trommeled  over  %-in.  screens.  The  proportions  were 
1:3:5  in  wall  plates,  end  plates  and  dividers,  and  1:2:4  in  studdles. 
The  reinforcement  in  wall  and  end  plates  consisted  of  three  %-in.  monolith 
steel  bars  with  J^-in.  webs  crimped  on,  together  with  two  straight  %-in. 
monolith  bars.  The  dividers  were  reinforced  by  four  J^-in.  monolith  steel 
bars  wound  spirally  with  J^[-in.  steel  wire,  the  whole  presenting  a  column 
of  square  cross-section.  Studdles  were  reinforced  with  two  pieces  of 
old  wire  rope  134-in.  in  diameter.  Slabs  were  molded  for  the  shaft  lin- 
ing, the  materials  used  being  trap  rock  under  %  in.,  conglomerate  sand 
and  Kahn  expanded  metal  as  reinforcement;  the  mixture  was  1:2:4. 

In  molding,  2-in.,  No.  1  white  pine  was  used  for  the  forms.  The 
forms  were  soaked  in  Delaney's  wood  preservative  and  repainted  with 
preservative  on  the  interior  each  time  before  setting  up,  thus  insuring 
them  against  warping  and  prolonging  their  lives  indefinitely,  as  well  as 
securing  a  smooth  and  easy  parting  of  the  concrete  when  removed. 

The  labor  involved  in  making  the  sets  consisted  of  two  carpenters 
setting  up  forms  and  keeping  them  in  repair;  one  man  wheeling  forms 


126  ^DETAILS  OF  PRACTICAL  MINING 

on  to  skipways  ready  for  filling,  and  returning  used  forms  to  the  shop 
and  cleaning  them;  one  man  feeding  mixer  from  stockpiles  of  rock,  sand 
and  cement;  one  man  delivering  mix  to  forms  and  shoveling  material 
into  place;  and  one  mason  ramming  charge  into  final  positions.  With 
this  combination  of  men  as  many  as  four  complete  sets,  consisting  of  64 
separate  pieces,  have  been  molded  in  one  day  of  9  hr.  In  ordinary 
weather,  the  sides  of  the  forms  were  allowed  to  remain  in  position  over 
night  and  then  removed,  while  the  bottoms  were  left  in  place  another 
24  hr.  The  bottoms  were  removed  by  turning  the  pieces  on  their  sides 
where  they  were  left  to  harden  one  day  longer  before  removal  to  the  stock- 
pile. All  through  the  process  of  removal  the  sets  were  handled  with 
the  greatest  care  in  order  to  preserve  the  appearance  of  the  set  and 
prevent  cracking,  which  might  not  develop  so  as  to  be  visible  to  the 
eye  until  weathered.  All  skidways  used  in  making  and  storing  were 
brought  to  a  level  to  prevent  warping  and  bending  while  the  sets  were 
green,  in  order  to  insure  a  perfect  set  under  ground,  for,  unlike  timber, 
concrete  sets  cannot  be  brought  to  place  unless  perfectly  true.  Sets 
should  not  have  been  used  under  60  days  after  removing  forms,  although, 
through  the  reduction  of  the  stockpiles,  it  was  at  times  necessary  to 
install  pieces  of  14-day  sets;  the  greatest  care,  however,  was  observed  in 
handling  and  putting  these  in  place  underground.  Concrete  sets  one 
year  old,  which  had  been  subjected  to  all  kinds  of  weather,  can  be  abused 
somewhat  and  handled  almost  as  carelessly  as  timber. 

It  was  found  advisable  from  the  beginning,  because  of  the  great 
weight  of  the  wall  plates,  to  mold  them  in  two  sections,  one  section  span- 
ning the  ladderway  and  one  skipway,  and  the  other  section  spanning 
the  remaining  skipway.  These  two  sections  were  connected  when  in 
place  by  two  bolts  passing  through  holes  cored  for  the  purpose  and  two 
straps  of  iron  spanning  the  splice.  Studdles  were  made  for  4-,  5-  and 
6-ft.  sets,  to  accommodate  the  ground  passed  through. 

The  weights  of  the  different  pieces  comprising  the  sets  were  as  follows : 
Long  section  of  wall  plate,  1035  lb.;  short  section  of  wall  plate,  700  lb.; 
end  plate,  600  lb.;  divider,  645  lb.;  and  3  X  3-in.  studdles,  268  lb.;  a 
total  weight  of  8104  lb.  for  a  complete  set  of  16  pieces. 

Taking  the  weight  of  No.  1  western  fir  which  has  been  exposed  to 
the  weather  in  stockpiles,  as  33  lb.  per  cubic  foot,  the  concrete  set  weighed 
almost  three  times  as  much  as  a  12  X  12-in.  timber  set  which  the  concrete 
set  was  intended  to  replace.  Because  of  this  additional  weight  of  the 
concrete  set,  it  was  found  necessary  to  increase  the  usual  five  or  six  men 
on  the  timber  gang  to  seven.  In  a  vertical  shaft,  to  which  the  concrete 
sets  are  especially  adapted,  the  number  of  men  per  gang  might  be  re- 
duced. The  sets  were  hung  or  built  as  the  ordinary  timber  sets,  only 
requiring  an  additional  rope  and  block  with  which  to  swing  the  pieces 


SHAFTS  AND  RAISES  127 

into  place.  After  the  sets  were  wedged  to  line,  bottoms  were  put  in 
between  the  plates  and  the  surrounding  shaft  wall,  and  the  set  then  tied 
to  the  shaft  by  means  of  concrete  in  the  proportion  of  1:3:5.  The 
concrete  slabs  were  next  put  in  place  and  loose  rock  thrown  behind  them, 
filling  up  what  space  still  remained  between  the  set  and  the  wall  of  the 
shaft. 

After  the  set  was  in  place,  it  was  extremely  important  that  it  be  well 
protected  from  the  blasting.  For  this  purpose  there  were  used  flat 
timber  and  steel  plates  chained  to  the  under  side  of  the  plates  and  dividers, 
and  even  this  precaution  was  at  times  inadequate.  Where  the  ground 
was  breaking  easily,  the  sets  have  been  as  near  as  12  ft.  to  the  miners, 
and  again,  where  the  ground  was  especially  hard,  and  tough,  sets  40  ft. 
from  the  blast  have  been  cut  out.  In  dangerous  ground,  which  required 
timbering  close  up  to  the  sinking,  timber  sets  were  used,  but  had  not  time 
played  an  important  part  in  the  sinking,  no  ground  was  met  in  which 
concrete  sets  could  not  have  been  installed.  With  a  gang  of  seven  men, 
a  complete  set  can  be  installed  in  a  9-hr,  shift.  This  permits  a  sinking 
rate  of  more  than  100  ft.  per  month,  which  was  accomplished  at  the  two 
shafts. 

The  comparative  costs  of  the  concrete  and  timber  sets  delivered 
at  the  shaft  collar  is  striking.  The  concrete  set  was  delivered  for  $22.50, 
the  timber  set  for  $37.60.  These  figures  are  based  on  western  fir  at  $28 
per  1000  ft.,  f.o.b.  car;  crushed  rock  at  35  cts.  per  cubic  yard,  f.o.b. 
shaft;  conglomerate  sand  at  60  cts.  per  cubic  yard,  f.o.b.  shaft;  No.  1 
Portland  cement  at  $1.15  per  barrel,  f.o.b.  works;  reinforcement  at  $12 
per  set,  f.o.b.  factory. 

Relining  the  Hamilton  Shaft  (Lake  Superior  Mining  Institute). — 
The  No.  2  Hamilton  shaft  of  the  Chapin  mine  at  Iron  Mountain,  Mich., 
was  sunk  in  1891,  and  consisted  originally  of  six  compartments  as  shown 
in  Fig.  99,  two  for  skips  or  bailers,  4  ft.  8  in.  by  7  ft.;  two  for  cages,  4  ft. 
8  in.  by  4  ft.  6  in. ;  and  two  for  pipes,  etc.,  4  ft.  8  in.  by  2  ft.  0  in.,  taken  off 
the  ends  of  the  cage  compartments.  This  shaft  was  timbered  with 
16  X  16-in.  material  in  the  main  members,  the  sets  spaced  6  ft.  2j-£  in. 
center  to  center,  the  outside  lagged  with  2-in.  planks,  making  a  minimum 
rock  section  of  10  ft.  by  24  ft.  4  in. 

The  timbers,  due  to  long  service,  became  badly  decayed,  so  that  it 
was  necessary  to  reline  the  shaft  or  abandon  it.  Early  in  1911  it  was 
decided  to  make  it  a  permanent  outlet  for  the  Chapin  mine,  and  install 
in  it  the  permanent  electrical  centrifugal-pumping  equipment.  It  was, 
therefore,  necessary  to  reline  it  from  collar  to  bottom,  a  distance  of  1434 
ft.,  and  since  there  was  a  possibility  of  striking  a  heavy  flow  of  water  in 
the  underground  workings  at  any  time,  provision  had  to  be  made  so  that 
bailers  could  be  put  in  service  on  short  notice.  Since  it  was  to  be  the 


128 


DETAILS  OF  PRACTICAL  MINING 


permanent  outlet,  further  provision  had  to  be  made  for  column  pipes  and 
electric  cables.  To  provide  for  these  pipes  and  cables,  it  was  necessary  to 
increase  the  inside  dimensions  of  the  shaft  from  7  by  21  ft.  4  in.  to  9  by 
21  ft.  4  in.,  making  a  poured  concrete  wall  6  in.  thick.  The  outside 
dimensions  of  the  shaft  were  not  changed.  In  the  new  design,  the  shaft 
consists  of  eight  compartments:  Two  for  skips  or  bailers  and  two  for 
cages,  each  4  ft.  8  in.  by  6  ft.  4  in.;  three  for  pipes  and  cable  and  one 
for  ladder,  each  2  ft.  4  in.  by  4  ft.  8  in.,  the  skip  compartments  set  off  with 
concrete-slab  partitions.  The  arrangement  is  shown  in  Fig.  100. 

To  make  the  concrete  economically,  a  mixing  plant  was  built  near  the 
shaft.  The  dividers,  end  plates  and  slabs  were  made  in  steel  forms, 
placed  beneath  the  mixers  so  that  the  concrete  could  be  poured  directly 
into  them.  After  the  concrete  had  sufficient  time  to  harden,  the  forms 
were  removed  and  the  molds  picked  up  by  a  hand-traveling  crane  and 
carried  into  a  drying  room,  where  they  were  cured.  The  design  of  these 
members  is  shown  in  Fig.  100. 


PIG.    99. PLAN  OF  OLD  SHAFT  LINING. 

The  actual  work  of  relining  was  done  in  sections,  each  section  being 
carried  upward  from  permanent  bearers  which  were  set  to  support  the 
old  timber  sets.  A  set  or  two  of  old  timber,  usually  12  ft.,  was  removed, 
loaded  on  the  cages  and  hoisted  to  the  surface.  The  timber  sets  above  the 
removed  portions  were  supported  by  vertical  columns  with  jack  screws 
on  the  bottom,  which  rested  on  12  X  12-in.  timber  placed  on  the  bearers. 
After  the  first  6-ft  section  of  concrete  was  poured,  the  12  X  12-in.  timbers 
were  placed  on  the  reinforced-concrete  dividers  and  end  plates,  which 
were  themselves  supported  on  the  steel  wall-forms,  as  shown  in  Fig.  101. 
The  steel  forms  were  made  in  sections,  with  recesses  to  support  end  plates 
and  dividers,  and  spaced  on  either  4-ft.  or  6-ft.  centers.  The  original 
forms  were  designed  for  4-ft.  centers;  when  the  6-ft.  spacing  was  used,  a 
section  was  bolted  to  the  top  of  the  form.  Since  there  were  seven  sets  of 
steel  forms,  the  footings  to  carry  the  weight  of  old  timber  sets  bore  either 
on  the  permanent  bearers  or  on  at  least  five  sets,  30  ft.,  of  concrete,  i.e.y 
the  support  of  the  old  timbers  above  did  not  depend  upon  green  concrete. 


SHAFTS  AND  RAISES 

-C   \  :/ 1  -  ,   ,  i  .  ,   c  \i,i    I-  ,  D, 


129 


Section  A-A. 


Section  B-B 
ARRANGEMENT    OF     CONCRETE       LINING 


Section  t-0 


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, 

'*-—#*-        -T*I 

3        llr 

i;  I;             ;i  ;1      •  F 

'Detail  of  Outer  Divider 


I****! 


L 

^.._._...   ^ .... 

r    -2-*~~>|^-— • 


Detail  of  5  Inth  Divider 


yt,       « 


Thistxvelis 
a  tight  fit 
in  the  X7 
divider 


'todstobe 
ben+onfieft 


i  . 

•i                   i!                   ii 

i 

Detail  of  Sub- 
Divider 


.. 

H 

1 

<  —  2- 

»-^-'yt?'-  

> 

;| 

II     11 

1!    » 

•i  li 

ii 

(A)  (B) 

Detail  of 'Slabs 


<—- 20"  —• 

"  -9: 


(C) 


1 


Detail  of  Stabs 


Detail  of  Right  Hand  End  Plate  (H) 

DETAIL  OF  CONCRETE  DIVIDERS   AND    SLABS 
FIG.    100. — NEW  CONCRETE  LINING  OF   HAMILTON    SHAFT,   IN   DETAIL   AND   ASSEMBLED. 


130 


DETAILS  OF  PRACTICAL  MINING 


After  a  new  set  of  steel  forms  was  lowered  in  the  cages  and  installed, 
the  dividers  and  end  plates  were  lowered  and  placed  in  the  recesses  pro- 
vided in  the  steel  forms,  with  their  ends  bolted  to  the  forms.  These  end 
plates  and  dividers  served  as  horizontal  struts  to  hold  the  forms  in  posi- 
tion. When  a  section  was  placed,  the  vertical  reinforcing  rods  were  put 
in  position  and  the  wall  was  ready  to  be  poured.  The  dividers  and  end 
plates  had  projecting  reinforcement  rods  for  anchoring  the  wall. 

The  concrete  for  the  wall  was  mixed  in  the  surface  mixing  plant  and 
discharged  into  side-dump  steel  cars,  which  were  hand  trammed  to  the 
shaft.  A  turntable  was  installed  so  as  to  serve  both  skip  compartments. 
The  concrete  car  was  run  on  a  cage  and  lowered  into  the  shaft.  A  revolv- 


CROSS- SECTION  LONGITUDINAL  SECTION 

PIG.    101. METHOD    OF    INSTALLING    LINING,    HAMILTON    SHAFT. 

ing  chute  was  attached  to  the  spout  of  the  car  and  the  contents  were 
discharged  behind  the  forms  and  properly  tamped  in  place.  Where 
large  crevices  occurred,  they  were  filled  to.  within  10  in.  of  the  steel  forms 
with  large  stones  or  rock  from  the  over-size  bin  before  the  concrete  was 
poured.  The  average  amount  of  material  for  relining  one  6-ft.  vertical 
section  of  shaft  was  1  cord  of  stone  for  backfilling,  10  cu.  yd.  of  con- 
crete, and  550  Ib.  of  steel  for  reinforcing.  The  slabs  for  the  skipway 
partitions  were  bolted  to  the  dividers. 

In  removing  old  timber,  five  men  were  required  below  and  one  man  at 
the  collar.  The  time  required  to  remove  one  6-ft.  section  varied  ac- 
cording to  the  condition  of  the  material.  In  placing  steel  forms  or  pour- 
ing concrete,  four  men  were  required  below  and  two  at  the  collar.  This 


SHAFTS  AND  RAISES  131 

does  not  include  the  shaft  foreman  or  the  concrete  foreman,  as  these 
two  men  did  not  spend  all  their  time  on  this  particular  job.  The  work 
was  carried  on  with  three  8-hr,  shifts  and  the  average  time  required  to 
concrete  6  ft.  of  shaft  was  24  hr.,  including  placing  the  forms,  pouring 
concrete  and  removing  an  equal  number  of  forms  from  below.  When 
the  forms  were  removed  they  were  taken  to  the  surface,  thoroughly 
cleaned  and  given  a  coat  of  crude  oil  before  they  were  used  again. 

The  first  section  of  relining  was  started  on  May  3,  1912,  83  ft.  3  in. 
below  the  collar,  and  the  lining  between  this  point  and  the  collar  was 
completed  June  29.  The  fifth  section  was  started  at  917  ft.  May  17, 
1913,  and  on  July  5,  813  ft.  of  shaft  was  completed.  The  average 
rate  of  progress  over  this  time,  without  deducting  the  time  due  to 
delays,  was  56.7  ft.  per  month  and  63  ft.  per  month  for  actual  working 
time.  The  progress  for  the  last  month  was  72  ft.  The  preliminary 
estimate  was  based  on  relining  100  ft.  per  month.  The  old  shaft  timbers, 
however,  were  in  far  worse  condition  than  could  possibly  be  anticipated, 
and  the  slower  progress  was  due  entirely  to  the  difficulty  in  removing 
them  and  the  precautions  required  to  protect  the  lives  of  men  employed 
on  this  work. 

In  the  portion  of  shaft  completed  to  the  date  of  writing,  all  the  work 
proved  perfectly  satisfactory  and  entirely  up  to  expectations.  The  walls 
were  smooth  and  waterproof.  The  reinforced-concrete  dividers  and  end 
plates  came  from  the  steel  forms  perfectly  true,  straight  and  smooth, 
and  fitted  perfectly  in  the  recesses  provided  in  the  steel  forms. 

Unit  Concrete  Sets  from  Central  Factory  (By  L.  D.  Davenport). — 
The  Oliver  Iron  Mining  Co.  erected  a  concrete  plant  at  Hibbing,  Minii., 
for  making  building  blocks,  shaft  sets,  slabs  and  similar  products  for 
use  at  its  new  mines  on  the  Mesabi  range.  The  structure  is  a  frame 
building  covered  with  corrugated  sheet  iron.  It  is  115  ft.  long  over  all 
and  consists  of  a  main  plant,  24  X  57  ft.,  four  stories  high,  and  a  one- 
story  shed  46  X  91  ft.,  divided  into  drying  and  steam  rooms. 

The  sand  and  rock  for  the  concrete  are  brought  in  stripping  cars 
from  one  of  the  openpit  mines  and  dumped  close  to  the  plant.  This 
material  as  needed  is  trammed  in  a  small  car  over  a  low  trestle  to  the 
crusher.  From  the  crusher  a  belt  conveyor  carries  the  crushed  material 
to  a  trommel  at  the  top  of  the  plant,  where  it  is  sized  and  deposited  in 
three  bins  as  shown  in  the  flow  sheet.  A  30-hp.,  200-volt,  Westinghouse 
motor  runs  the  crusher,  the  trommel  and  the  conveyor  belt.  The 
cement  is  brought  to  the  plant  in  railroad  cars  over  a  trestle  at  the  ele- 
vation of  the  charging  floor  and  is  unloaded  and  stored  under  the  bins 
conveniently  near  the  charging  car.  Below  the  bins  is  a  track  carrying 
a  wedge-shaped  charging  car  which  is  divided  into  compartments  for 
sand,  rock  and  cement.  The  charging  car  dumps  directly  into  a  No.  1 


132 


DETAILS  OF  PRACTICAL  MINING 


Smith  mixer,  water  being  added  from  a  tap  close  by.  This  charging  car 
is  also  used  to  tram  the  oversize  from  the  screens  to  a  chute  leading  back 
to  the  crusher.  From  the  mixer  the  concrete  is  taken  to  one  of  three 
chutes  by  a  transfer  car  of  the  same  pattern  as  the  charging  car  except 
that  it  is  not  divided  into  compartments.  One  of  the  chutes  feeds 
a  Denver  block  machine  and  the  other  two  supply  the  various  forms 
placed  below  them.  All  blocks  are  cured  in  the  steam  room  and  the 
shaft  sets  are  either  sent  to  the  steam  room  or  are  dried  in  the  main  shed, 
which  is  steam  heated.  The  finished  product  is  taken  from  the  trucks 
and  piled  or  loaded  on  freight  cars  by  means  of  an  air  lift  of  about  5 


WIRE  MESH  %'D  OPENINGS- 
PLATE  1$  xtf  'OPENIN6%j, 


T  T  I 


VARIOUS   FORMS 


TO  STEAM  ROOM 


TO  DRYING  ROOM 


OR  STEAM  ROOM 


U M4?—tt 91-0'-' 

FLOOR  PLAN  OF  CONCRETE  PUNT 


FLOW  SHEET 
FIG.    102. HANDLING  MATERIAL  AT  MANUFACTURING  PLANT. 


tons'  capacity,  running  on  an  overhead  crane.  The  arrangement  of  the 
building  and  the  successive  steps  in  handling  the  material  are  shown 
in  Fig.  102. 

A  1 : 4  mixture  of  cement  and  sand  is  used  in  the  blocks  and  a  1:2:4 
or  a  1:2:3  in  the  shaft  sets.  Three  complete  shaft  sets,  i.e.,  six  wall 
plates,  six  end  plates,  six  dividers,  24  studdles  and  156  slabs  for  lagging, 
and  from  500  to  700  9  X  24-in.  building  blocks  constitute  an  average 
day's  output  under  favorable  conditions. 

The  concrete  shaft  sets  are  cast  in  forms  built  up  of  steel  plates  and 
angles  with  all  holes  cored  tapering  about  %  in.  larger  than  the  bolts  to 


SHAFTS  AND  RAISES  133 

be  used.  A  1:2:4  mixture  was  used  at  first,  but  this  was  changed  to  a 
1:2:3  in  order  to  obtain  a  smoother  product.  The  concrete  is  made 
wet  and  puddled  in  the  forms  rather  than  rammed.  The  wall  plates  and 
end  plates  are  12  X  12  in.,  and  the  dividers  are  10  X  12  in.  The  corner 
studdles  are  10  X  10  in.  and  the  center  studdles  are  8  X  10  in.  The 
studdles  being  4  ft.  long,  the  sets  are  spaced  on  5-ft.  centers.  The 
general  style  of  framing  is  the  same  as  for  the  standard  wood-lined  shaft 
6  X  18  ft.  inside,  with  the  exception  of  a  few  details  as  follows:  A  2  X  2- 
in.  cleat  spiked  in  the  center  of  the  outside  of  the  wooden  sets  makes  a 
bearing  for  the  lagging,  while  the  upper  and  lower  outside  edges  of  the 
concrete  sets  are  rabbeted  1%  X  3  in.  to  hold  the  concrete  lining  slabs. 
The  details  of  the  members  and  the  arrangement  at  the  collar  are  shown 
in  Fig.  103. 

The  shaft  is  hung  from  four  steel  crossbearers  which  in  turn  rest  on 
two  reinforced-concrete  longitudinal  bearers  about  2  X  3  ft.  in  cross-sec- 
tion and  34  ft.  long.  These  were  cast  in  place  just  below  the  surface  of 
the  ground  from  the  outside  of  the  shaft.  The  crossbearers  at  each 
end  of  the  shaft  are  each  made  up  of  two  15-in.,  33-lb.  channels  19  ft. 
long.  Those  at  the  dividers  are  single  15-in.,  42-lb.  I-beams  of  the 
same  length.  The  shaft  collar  including  all  the  shaft  above  the  first 
bearers  was  cast  in  one  piece  with  12-in.  outside  walls  and  10-in.  dividers. 
The  placing  of  the  first  two  or  three  sets  directly  below  the  bearers 
presented  a  slightly  different  problem  from  the  ordinary  timbered  shaft 
on  account  of  the  solid  concrete  collar  section  above  the  bearers.  In  a 
timbered  shaft  the  dividers  are  left  out  of  the  collar  set  until  the  next 
two  or  three  sets  below  have  been  hung.  With  a  6-  or  8-ft.  monolithic 
collar  section  including  the  dividers,  there  is  not  room  to  lower  and  swing 
into  place  the  20-ft.  wall  plates  for  the  next  two  or  three  sets  except  by 
sinking  18  or  20  ft.  without  timber.  This  difficulty  was  overcome  by 
driving  a  2  X  3-ft.  flat  incline  from  the  surface  to  a  point  just  under  the 
crossbearer  at  one  end  of  the  shaft.  The  concrete  timbers  were  slid 
down  this  incline  and  hung  in  place  until  the  shaft  was  sufficiently  deep 
to  allow  lowering  in  the  ordinary  manner. 

The  skip  guides  are  of  wood  and  are  fastened  to  the  end  pieces  with 
3M  X  %G  X  7-in.  angles  and  to  the  dividers  by  7^-in.  lengths  of  10- 
in.,  25-lb.  channels.  All  ladderway  sollars  are  %Q-in.  hob  steel  plates 
with  steel  toe-boards  of  2  X  2  X  %-in.  angles  around  the  ladder  open- 
ings and  of  5  X  3J£  X  %-in.  angles  on  the  pipeway  side.  The  ladders 
are  made  of  1>^  X  1M  X  J^-in.  angles  with  %-in.  pipe  rungs  spaced 
10-in.  centers.  Two  pieces  of  \Y±  X  lj^-in.  flat  iron  cover  the  ends  of 
the  rungs  and  are  held  by  %-in.  bolts  through  the  rungs  and  angles.  The 
ladders  are  about  24  ft.  long  and  extend  4  ft.  through  the  sollars  to  the 
under  sides  of  the  sets  above,  making  excellent  hand  holds.  The  ladder- 


134 


DETAILS  OF  PRACTICAL  MINING 


SHAFTS  AND  RAISES 


135 


way  is  separated  from  the  skipway  with  a  No.  26A  galvanized  rein- 
forcement mesh. 

Gunite  Casing  on  Wood  Shaft  Lining  (By  Stephen  Royce). — An 
experiment  tried  at  "A"  shaft  of  the  Gary  mine,  operated  by  Pickands, 
Mather  &  Co.  at  Hurley,  Wis.,  on  the  Gogebic  range,  consisted  of  cover- 
ing the  steel  sets  and  wood  lath  with  cement  mortar  applied  with  a  cement- 
gun.  The  shaft  arrangement  is  shown  in  cross-section  in  Fig.  104. 
The  inclination  is  73°  10'.  The  steel  sets  are  spaced  at  4-ft.  intervals 
and  the  3-in.  hemlock  lagging  is  wedged  into  the  flanges  of  the  I-beams,  as 
shown.  The  sets  were  blocked  into  place  by  wooden  blocking,  with 


Reinforcement 
Triangular  IMesh 


Original  method 
/of  fastening 


DETAIL  OF  GUNCRETE  CASING 
OK  I-BEAM  DIVIDERS 

PIG.    104. SHAFT  ARRANGEMENT  AND  DETAILS  OF  COATED  MEMBERS. 


bearers  put  in  at  intervals  of  about  50  ft.  At  the  several  level  openings 
the  shaft  was  completely  concreted  before  the  cement-gun  work  was 
contemplated.  The  total  depth  of  the  shaft  is  1290  ft. 

The  hemlock  lagging  showed  signs  of  rotting  out  and  of  course  it 
permitted  free  circulation  of  air  behind  the  sets,  which  it  was  feared  would 
rot  the  blocking  and  so  throw  the  shaft  out  of  line.  In  order  to  fire- 
proof the  wooden  lining,  to  protect  the  steel  work  from  rust,  to  ex- 
clude air  from  the  spaces  between  the  sets  and  the  outside  rock,  and  to 
keep  all  the  wood  uniformly  wet  so  as  to  discourage  decay,  a  coating  of 
l}4-in.  " Gunite,"  as  the  material  applied  by  the  cement-gun  process 


136  DETAILS  OF  PRACTICAL  MINING 

is  called,  was  decided  upon.  This  has  been  tried  in  two  experimental 
sections  of  the  shaft  having  a  total  length  of  263  ft. 

The  cement-gun  is  an  apparatus  designed  to  shoot  through  a  nozzle 
a  stream  of  mixed  cement,  sand  and  water  in  about  4  : 1  mixture.  One 
of  the  advantages  claimed  for  mortar  shot  on  by  this  process  is  that 
the  mixture  is  automatically  enriched  where  most  needed  and  is  less 
rich  where  a  poorer  mixture  is  sufficient.  This  results  from  the  tendency 
of  the  particles  of  sand  to  rebound  as  soon  as  they  hit  a  hard  surface,  so 
that  the  first  J£  or  Y±  in.  will  consist  of  almost  neat  cement.  This  ma- 
terial sets  almost  as  soon  as  it  strikes  and  the  full  benefit  of  the  set  is  given 
to  the  work,  there  being  no  possibility  that  the  cement  may  partially  set 
between  the  time  of  mixing  and  the  time  of  applying. 

The  delivery  hose  is  made  of  pure  soft  rubber,  covered  with  heavy 
canvas  and  may  be  as  much  as  300  ft.  or  more  in  length.  The  wearing 
out  of  the  delivery  hose  is  one  of  the  chief  expenses  of  operating;  one 
hose  may  last  for  from  two  to  six  weeks,  according  to  the  character  of 
the  sand  that  is  fed. 

Of  the  two  sections  of  shaft  covered  in  this  work,  one  extended  from 
the  collar  to  the  3rd  level,  the  other  from  the  8th  to  the  10th  level.  In 
the  upper  section  the  machine  was  placed  on  the  surface  and  the  delivery 
hose  was  carried  down  through  the  shaft  to  the  point  where  work  was 
being  done.  In  the  lower  section  the  machine  was  set  on  the  8th  level. 
Material  and  supplies  were  handled  in  a  temporary  cage  in  the  center 
compartment,  no  hoisting  being  done  in  the  shaft  at  this  time. 

The  walls  were  reinforced  with  No.  7  American  Steel  &  Wire  Co. 
triangular  mesh  and  the  dividers  with  1%-in.  chicken  wire,  held  on 
with  wire  clamps.  Fig.  104  shows  two  methods  of  attachment  of  the 
reinforcing  wire  to  the  steel  sets.  The  first  method  used  nails  and 
staples.  This  was  discarded  because  it  placed  too  much  dependence 
upon  the  holding  power  of  the  staples  in  the  hemlock  planks,  which  might 
later  decay.  The  second  method  depends  entirely  upon  the  strength  of 
the  staples,  which  hold  directly  on  the  steel,  and  was  adopted  for  most 
of  the  work.  The  reinforcing  wire  was  also  stapled  to  the  lagging  at 
intervals  between  the  sets.  The  dividers  were  filled  in  completely  on 
their  upper  faces,  the  result  being  a  considerable  increase  in  their 
ability  to  resist  a  downward  load.  This  increase  of  strength  is  figured 
at  nearly  20  per  cent. 

The  results  seem  to  have  been  entirely  favorable.  There  is  a  solid 
hard  coating  of  concrete  over  the  entire  sides  and  all  the  steel  work  in 
the  shaft.  This  coating  seems  to  be  completely  waterproof,  so  much 
so  in  fact  that  it  was  considered  necessary  to  set  pipes  in  the  bottom 
of  each  section  coated  in  order  to  prevent  the  water  from  banking  up 
behind  the  shaft  covering  and  causing  heavy  hydrostatic  pressure.  What 


SHAFTS  AND  RAISES 


137 


the  effect  will  be  upon  the  life  of  the  lagging  and  of  the  blocking  be- 
hind the  sets  is  not  known,  of  course,  as  yet,  but  from  the  uniform  and 
apparently  airtight  character  of  the  coating,  it  is  hoped  that  it  will  greatly 
increase  the  life  of  the  wood.  If  the  lagging  partially  rots,  the  reinforce- 
ment is  so  solidly  fastened  to  the  steel  that  it  should  take  up  a  con- 
siderable part  of  the  stress  now  borne  by  the  lagging. 

Concreting  Methods  in  Copper  Range  Shafts. — In  the  Baltic  mine 
the  concrete  support  for  the  roof  of  the  shaft  is  reinforced  with  IJ^-in. 
ropes,  three  carried  down  each  skipway  and  stretched  between  eye-bolt 
anchorages.  The  ropes  are  stretched  until  at  the  center  they  are  about 
6  in.  from  the  edge  of  the  concrete.  At  intervals  of  8  to  14  in.,  cross- 
reinforcement  of  the  same  material  is  put  in.  Alternate  ropes  of  this 
cross-reinforcement  are  turned  up  about  one-third  of  the  way  out  from 


'Double  Sirand' 
Unlaid  from 


levation        „        __-  Section  A-B 

FIG.    105. ROPE  REINFORCEMENT  IN  SIDE  LINING. 

the  side  walls  and  also  turned  up  to  pass  over  the  dividers  for  the  purpose 
of  taking  the  shear. 

Along  the  sides,  three  ropes  in  the  direction  of  the  shaft  afford  rein- 
forcement. Cross-reinforcement  in  these  side  walls  consists  of  double 
strands  unlaid  from  lj^-in.  cable.  These  are  set  in  a  vertical  plane  and 
at  right  angles  to  the  long  axis  of  the  shaft,  about  2  ft.  apart  and  4  in. 
from  the  face  of  the  concrete.  Fig.  105  shows  the  general  arrangement. 

When  there  is  continuous  concrete  on  the  hanging,  dividers  are  put  in 
10  in.  thick  and  6  ft.  along  the  shaft  with  6-ft.  spaces  between.  These 
are  shown  in  Fig.  106.  Three  IJ^-in.  ropes  in  the  direction  of  the  shaft 
and  three  pairs  at  right  angles,  spaced  as  shown,  afford  reinforcement. 
The  pair  lowest  in  the  divider  is  bent  at  the  ends  to  take  shear.  Bolts 
in  the  direction  of  the  shaft  axis  are  set  in  at  top  and  bottom  of  the  divider 
and  serve  to  carry  3-in.  nailing  strips  to  which  the  planks  covering  the 


138 


DETAILS  OF  PRACTICAL  MINING 


spaces  between  the  dividers  are  nailed.  These  nailing  strips  are  set  back 
2  in.  so  that  the  planks  are  flush  with  the  concrete  and  are  thus  protected 
against  being  knocked  off  by  falling  rock. 

In  case  the  hanging  wall  stands  but  the  sides  give  trouble,  the  latter  are 
reinforced  as  described  and  dividers  also  set,  but  with  the  spaces  between 
increased  to  10  ft.  To  take  the  side  thrust  of  the  walls,  a  cross-beam 
against  the  hanging  is  put  in  about  every  25  ft.  This  is  10  to  18  in.  thick 
and  4  ft.  wid'e  as  shown  in  Fig.  107.  This  brace  is  reinforced  with  three 
IJ^-in.  ropes  across  the  shaft.  It  has  its  top  face  beveled  to  prevent 
material  from  lodging.  These  beams  are  set  at  the  same  points  as  the 
dividers  so  as  to  be  braced  against  side  bending. 

The  stations  are  equipped  with  concrete  brow-pieces  over  the  skip- 


Section  A-B 


TIG.    106. 


Front  Elevation 


CONCRETE    AND    PLANK 
DIVIDER. 


FIG.    107. HANGING- 
WALL    CROSSBEAM. 


ways,  shown  in  Fig.  108.  These  are  reinforced  with  a  grilling  of  double 
strands  across  and  single  strands  in  the  direction  of  the  shaft,  so  put  in  as 
to  form  6-in.  squares.  The  angle  at  the  floor  of  the  station  is  strengthened 
with  a  55-lb.  rail. 

In  the  Champion  shafts,  the  roof  reinforcement  of  IJ^-in.  rope  is  put 
in  as  a  network  in  the  manner  shown  in  Fig.  109.  The  cross-ropes  are 
strung  through  eye-bolts  and  carried  up 'and  across  in  a  zigzag  manner. 
The  ropes  in  the  direction  of  the  shaft  are  anchored  only  at  the  top  and 
bottom.  The  ropes  in  the  network  are  clamped  at  the  crossing  points 
and  ends.  The  approximate  spacing  is  as  shown. 

Concrete  Collar  for  Mohawk  Shaft. — Incline  shafts  of  the  Lake  Su- 
perior copper  district  are  now  commonly  equipped  with  a  concrete  shaft 


SHAFTS  AND  RAISES 


139 


collar  to  keep  out  surface  water  and  to  keep  fires  from  extending  under- 
ground. Generally  the  shafts  have  to  be  sunk  through  a  considerable 
depth  of  overburden,  often  a  sort  of  quicksand.  The  general  procedure 
is  to  strip  a  large  enough  area  of  overburden  to  open  a  pit  in  which  the 
sides  stand  at  the  angle  of  repose  of  the  material  without  interfering  with 


Station  floor       .55  1  b.  fail 


Section  Front  Elevation 

FIG.    108.  -  CONCRETE    STATION  BROW  REINFORCED. 

the  putting  in  of  the  shaft  collar.  The  concrete  collar  is  started  from  a 
bench  cut  down  to  solid  rock  so  as  to  permit  making  a  water-tight  joint 
between  the  rock  and  the  collar.  After  the  collar  is  finished,  the  ground 
is  piled  in  again  to  fill  the  excavation. 

At  Mohawk  No.  6  shaft,  the  collar  was  99  ft.  long  with  outside  dimen- 
sions of  22  X  11  ft.  and  walls  12  in.  thick;  the  overburden  was  45  ft.  deep. 


K 


FIG.    109. ROPE  REINFORCEMENT  ON  HANGING  WALL. 

The  concrete  was  poured  down  troughs  from  a  mixer  at  the  top.  In  order 
to  keep  the  concrete  from  separating  as  it  went  down,  splash  boards  were 
put  in  the  troughs  every  few  feet  to  retard  the  descent.  At  the  bottom 
the  concrete  was  caught  on  a  platform,  turned  over  with  a  shovel  and 
then  shoveled  into  the  forms.  As  the  work  progressed  upward,  the  plat- 
form was  raised.  A  1:3:5  mixture  was  used,  the  aggregate  being  rock 


140 


DETAILS  OF  PRACTICAL  MINING 


from  the  mine,  crushed  to  pass  a  2-in.  screen,  with  the  fines  left  in. 
Knockdown  forms  of  wood  were  used,  being  moved  up  as  concreting  pro- 
gressed. Fig.  110  shows  the  manner  of  building  the  forms,  and  the  way 
that  they  were  held  in  place  by  braces  and  bolts  on  the  inside  as  well 
as  on  the  outside. 

For  reinforcing,  discarded  IJ^-in.  hoisting  cables  were  used.  This 
rope  was  put  in  to  form  the  cross-rods  for  strengthening  the  bottom,  top 
and  sides  of  the  collar,  and  each  alternate  rope  was  turned  up  at  the  ends 
at  an  angle  of  45°  to  take  care  of  the  shearing  stresses  near  the  ends.  The 
rope  was  assumed  to  have  half  the  strength  of  an  iron  bar  of  the  same 
area,  and  the  area  of  the  rope  reinforcement  at  the  bottom  of  the  collar 
was  kept  at  about  2  per  cent,  of  the  sectional  area  of  the  walls.  The  ropes 
were  spaced  at  intervals  of  6  in.  in  the  lower  part,  but  the  spacing  was 
increased  toward  the  top  until  it  was  about  10  in.  The  ropes  were  placed 
in  the  forms  so  that  they  would  be  about  an  inch  from  the  inside  surface 
of  the  walls,  approximately  one-tenth  the  depth  of  the  wall. 


FIG.   110. CONCRETE  COLLAR  OF  THE  MOHAWK  SHAFT. 

The  divider  columns  were  12  X  18  in.  in  section  reinforced  by  four 
%-in.  bars  wound  with  3^-in.  rods  to  hold  them  in  position  with  respect  to 
one  another.  The  rods  for  strengthening  the  dividers  were  fastened  to 
two  pieces  of  hoisting  cable  that  ran  down  along  each  line  of  dividers, 
and  reinforced  a  beam,  6  in.  deep,  which  connected  the  dividers. 

Heavy  poultry  netting  was  put  in  the  collar  as  centering  to  hold  the 
pieces  of  rope  in  their  proper  relation  to  one  another  and  to  the  forms; 
to  this  the  rope  was  wired.  After  this  netting  and  the  ropes  had  been 
nailed  to  the  inside  forms,  the  outside  forms  were  erected  around  it,  and 
the  concrete  was  shoveled  in.  The  planks  of  the  top  form  were  nailed 
on  as  fast  as  the  forms  were  filled  with  concrete.  After  about  four  forms 
had  been  filled,  and  the  concrete  in  the  bottom  form  had  set  about  a  day 
and  a  half,  the  outside  forms  of  the  bottom  section  were  removed  by 
loosening  the  top  bolt  and  knocking  out  the  side  braces,  while  the  inside 
forms  for  the  walls  and  the  columns  were  also  taken  off.  The  forms  were 
then  reerected  and  used  again. 

The  100  ft.  of  collar  was  completed  in  17  days  after  the  beginning 


SHAFTS  AND  RAISES 


141 


of  concrete  work.  In  its  construction  9000  ft.  of  lj^-in.  hoisting  cable 
weighing  9  tons  was  used  together  with  176  rods  %-in.  in  diameter  and 
11  ft.  long,  weighing  about  1%  tons;  888  ft.  of  %-m.  rod  weighing  147  lb., 
4500  sq.  ft.  of  heavy  poultry  netting;  16,  45-lb.  rails;  two  60-lb.  rails  and 
12,000  bd.  ft.  of  pine.  The  rails  were  used  in  reinforcing  the  bottom  of 
the  collar  where  it  was  seated  on  the  ground.  The  total  cost  was  $3931. 

Concrete  Shaft  Collar  at  the  Wolverine. — At  the  Wolverine  No.  5 
shaft,  sunk  to  prospect  the  Osceola  lode,  a  concrete  collar  was  put  in 
56  ft.  long  and  22  X  11  ft.  in  section;  outside  measurements.  The  rein- 
forcement was  applied  in  a  manner  different  from  that  used  at  the 
Mohawk  No.  6,  partly  because  of  less  depth  of  overburden,  only  16  ft. 
Triangular-mesh  reinforcement  was  used  to  carry  the  ropes  in  the  forms 
as  well  as  to  aid  in  reinforcing  the  collar. 

In  prospecting  for  the  lode  it  was  necessary  to  trench  through  the 
overburden.  This  trenching  dried  up  the  wells,  as  the  shaft  is  in  a  small 


FIG.    111. CISTERN  FOR  COLLECTING  BOILER  WATER  ABOVE  CONCRETE  COLLAR. 

gully  draining  the  country  near-by.  In  order  to  restore  the  wells  to  use 
and  to  enable  the  making  of  a  well  for  supplying  the  boiler  plant,  it  was 
decided  to  make  the  collar  also  serve  as  a  dam  to  back  up  the  water.  A 
funnel  was  put  through  the  concrete  to  let  the  water  into  the  shaft  while 
the  collar  was  being  erected.  Then,  after  the  collar  had  been  completed, 
the  surface  that  was  to  be  toward  the  water  was  coated  with  tar  to  help 
make  it  waterproof.  To  make  a  cistern  for  the  boilers,  a  dry  wall  of 
rough  masonry  was  put  in  on  the  bottom  of  the  shaft  trench,  as  shown  in 
Fig.  Ill,  and  a  tank  with  concrete  walls  was  erected  on  that  as  a  founda- 
tion. This  tank  was  covered  with  concrete,  a  terra-cotta  tile  24  in.  in 
diameter  being  inserted  in  the  top  to  serve  as  a  manhole.  After  this  tank 
had  been  completed  a  piece  of  waste  saturated  with  cement  was  inserted 
in  the  funnel  and  rammed  tight.  This  shut  off  the  flow  of  water  into 
the  shaft  almost  instantly,  and  concrete  was  then  poured  in  on  top  of  the 
waste.  Next,  large  boulders  were  piled  in  the  pit  around  the  shaft  and 


142  DETAILS  OF  PRACTICAL  MINING 

tank,  and  finally  dirt  was  put  on  top,  and  the  concrete  cistern  completely 
covered  over  with  dirt. 

The  water  rose  in  the  cistern  and  reserve  for  the  boilers  was  obtained, 
as  the  water  would  filter  through  the  loose  rock  around  the  collar  and  up 
through  the  loose  masonry  at  the  bottom  of  the  tank  into  the  cistern  as 
fast  as  it  was  pumped  from  it.  About  16,000  gal.  of  water  was  thus  stored 
back  of  the  dam,  and  the  water  rose  to  a  height  of  about  12  ft.  above  the 
place  where  the  collar  was  seated  on  solid  ground;  little  seepage  resulted. 

Owing  to  the  fact  that  triangular-mesh  reinforcement  was  used  to 
center  the  rope  reinforcement  in  the  forms,  and  that  the  depth  of  burden 
was  only  16  ft.,  the  pieces  of  old  hoisting  cable  were  put  in  7  in.  apart  at 
the  bottom.  As  the  collar  grew  in  height  the  interval  was  increased  to 
10  in.  Only  at  the  bottom  were  the  side  walls  reinforced.  In  other 
respects  the  reinforcement  was  similar  to  that  used  in  the  Mohawk;  the 
knock-down  forms  and  the  delivery  of  the  concrete  by  sliding  it  down 
troughs  to  a  plat  whence  it  was  shoveled  into  the  forms,  were  adhered  to. 

Concrete  Drop  Shaft  (By  Claude  T.  Rice). — The  shaft  for  opening  the 
newly  discovered  lode  of  the  Indiana  Mining  Co.,  in  the  Lake  Superior 
copper  region,  had  to  be  sunk  through  100  ft.  of  overburden,  in  the  upper 
60  ft.  of  which  there  was  sand  and  clay,  followed  for  about  20  ft.  by  mate- 
rial in  which  quicksand  and  clay  prevailed  and  in  which  were  one  or  two 
seams  of  sand  and  gravel  about  1  ft.  thick.  From  70  to  77  ft.  from  the 
surface,  the  material  was  hardpan  succeeded  by  sand,  clay,  and  quick- 
sand, which  extended  to  hard  rock.  This  overburden  was  penetrated 
by  a  concrete  drop  shaft.  The  drop-shaft  casing  was  made  of  annular 
sections  of  steel  plate,  18  ft.  in  diameter  at  the  bottom,  but  with  each 
ring  of  slightly  smaller  diameter,  so  that  each  one  bolted  inside  the  one 
below.  The  sections  were  overlapped  4  in.  The  two  lowermost  rings 
were  of  J^-in.  plate;  those  above  were  % g  in.  thick.  A  %  X  6-in.  angle 
was  fastened  to  the  bottom  plate  to  stiffen  the  bottom  and  give  a  some- 
what stronger  cutting  edge.  This  angle-iron  ring,  furthermore,  facili- 
tated the  concreting  that  was  to  follow. 

The  first  50  ft.  of  the  shaft  was  sunk  in  winter  without  any  trouble 
being  experienced,  as  the  ground  froze  and  stood  without  support.  The 
thickness  of  the  concrete  shell  was  proportioned  to  give  weight  enough 
to  overcome  a  frictional  resistance  of  400  Ib.  per  square  foot.  No  allow- 
ance, however,  had  been  made  for  the  fact  that  the  50  ft.  of  sand  that 
stood  without  support  would  offer  little  resistance  to  the  settling,  and,  as 
a  result,  the  drop-shaft  sank  down  through  the  overburden  faster  than  the 
sand  could  be  excavated,  causing  no  difficulty  other  than  that  the  cutting 
edge  was  bent  up  somewhat  by  forcing  boulders  out  of  its  path. 

The  concrete  lining  of  the  steel  ring  was  put  in  from  the  bottom  up; 
in  the  first  50  ft.,  collapsible  wooden  forms  were  used.  The  shaft  opening 


SHAFTS  AND  RAISES 


143 


within  the  lining  was  octagonal;  10-in.  channels  are  shown  in  the  center 
of  the  octagon,  Fig.  112.  These  were  put  in  at  6-ft.  centers,  to  carry  the 
center  guides,  which  in  this  concreted  part  of  the  shaft  are  6-in.  channels. 
The  end  guides  are  secured  by  brackets  set  in  the  concrete.  These 
brackets  were  not  put  in  until  after  the  drop-shaft  had  been  seated  upon 
solid  rock.  Instead,  blocks  of  wood  were  put  in  the  concrete  at  the  places 
where  the  brackets  were  afterward  to  be  set,  this  being  necessary  because 
the  drop-shaft  was  continuously  sinking  and  the  hoisting  and  lowering 
of  material  was  done  by  a  boom  derrick.  As  this  bucket  could  not  be 


Plate  —  > 


Plate--" 


x.6"  Angle  Ring  -^ 


FIG.    112. CONCRETE  DROP  SHAFT,  PLAN  AND  SECTION. 

used  with  guides,  had  the  brackets  been  set  in  place  at  first,  the  buckets 
would  have  caught  upon  them. 

After  the  concreting  in  the  first  50-ft.  section  of  the  drop-shaft  had 
been  carried  up  to  the  surface,  further  steel  plates  were  bolted  to  the 
top  of  the  completed  portion;  the  collapsible  wooden  form  was  moved  up, 
and  a  new  section  concreted,  the  operation  being  repeated  as  rapidly  as 
the  drop-shaft  sank.  Reinforcement  was  used  only  in  the  upper  10  or 
12  ft.  of  the  completed  drop-shaft,  consisting  of  a  few  wire  ropes,  in  1 :  3^ :  7 
concrete.  The  concrete  for  the  lower  part  of  the  shaft  was  a  1 : 2% :  5 
mixt'ure. 

When  solid  rock  was  reached,  the  material  remaining  within  this 


144 


DETAILS  OF  PRACTICAL  MINING 


shaft  was  excavated ;  a  smooth  shelf  was  cut  in  the  solid  rock  by  hammer 
and  drill;  and  the  joint  was  sealed  with  concrete.  Work  was  started 
Jan.  1,  1911,  and  the  drop  shaft  completed  about  Apr.  1;  the  total  cost 
was  $57.58  per  foot. 

CONCRETE  SKIP  STRINGERS 

Concrete  Stringers  for  Incline  Tracks   (By  Claude  T.  Rice). — In 
the  Michigan  copper  district  the  use  of  concrete  stringers  under  the  skip 


PIG    113. — ABANDONED  METHOD  OF  FASTENING  RAILS. 

tracks  for  the  amygdaloid  mines  is  standard  practice,  unless  the  footwall 
gives  trouble  from  swelling.  These  were  first  used  by  the  Ahmeek, 
and  the  method  of  fastening  the  rails  adopted  from  that  mine  by  the 
Mohawk  is  shown  in  Fig.  113.  The  method  has  two  disadvantages. 
In  the  first  place  a  large  amount  of  metal  is  used,  since  at  3-ft.  intervals 
there  is  a  channel  through  the  stringer  to  give  access  to  the  track  bolts, 
and  these  bolts  themselves  are  carried  in  pipes  and  require  bottom  plates 


CROSS-  SECTION 
OF  COMPLETED  TRACK 


SIDE  OF  FORM 


FIG.    114. IMPROVED  TYPE  OF  STRINGER  AND  FORM. 

and  beveled  clips  to  grip  the  rails.  A  more  serious  difficulty  is  the  fact 
that  when  a  skip  jumps  the  track  it  is  liable  to  cut  the  heads  of  the  bolts, 
which  cannot  then  be  extracted  and  replaced  except  by  cutting  the  bottom 
nut  or  the  bottom  of  the  bolt  itself. 

To  remedy  these  difficulties,  the  form  of  stringer  shown  in  Fig.  114 
was  devised  by  W.  F.  Hartman,  engineer  for  the  Mohawk  and  Wolverine 
companies.  Its  advantages  are  manifest.  The  use  of  channels  and  clips 
is  eliminated,  the  bolts  are  accessible  and,  in  the  most  improved  form,  the 


SHAFTS  AND  RAISES  145 

use  of  pipes  to  carry  the  bolts  is  avoided  by  inserting  %-in.  bolts  in  the 
forms  and  withdrawing  them  when  the  concrete  is  partly  set,  leaving  a 
suitable  hole  for  inserting  the  %-in.  bolts.  The  head  of  the  bolt  is  also 
less  exposed.  The  bolt  holes  are  enough  larger  than  the  bolts  so  that  an 
adjustment  of  ^  in.  in  the  alignment  of  the  track  is  possible.  The  system 
also  involves  the  use  of  2  X  4-in.  creosoted  ties  at  18-in.  intervals  to 
take  the  shock  of  the  skip  off  the  concrete. 

The  arrangement  of  the  forms  for  the  12  X  12-in.  stringer  is  shown 
in  Fig.  114,  and  the  method  of  supporting  these  and  the  forms  for  the 
foundations  of  the  stringers,  is  shown  in  Fig.  115.  The  2  X  4-in.  ties 
bind  the  tops  of  the  form  sides  during  pouring  and  1-in.  pieces  across  the 
bottom  perform  a  similar  function  there.  The  recesses  for  the  bolts  are 
formed  by  small  blocks  of  wood  nailed  to  the  sides  at  the  proper  intervals. 
The  forms  are  supported  on  2  X  4-in.  pieces  extending  across  the  shaft. 
Vertical  2-in.  planks,  nailed  to  the  form  sides  and  extending  to  the  shaft 
bottom,  serve  as  forms  for  the  concrete  foundation.  Before  concreting, 
the  shaft  foot-wall  is  carefully  cleaned.  The  forms  are  set  in  place  by 
timbermen  and  lined  up  by  a  surveyor  for  direction  and  dip. 

The  concrete  is  mixed  on  the  level  above  and  slid  down  in  18-  to  24- 
in.  troughs,  to  a  shoveling  platform  at  the  point  where  used.  The  work  is 
done  in  100-ft.  lifts.  A  crew  of  from  six  to  eight  men  can  pour  100  ft. 
of  double  track  in  24  hr.  As  fast  as  the  form  is  filled,  the  cover  is  nailed 
on.  The  forms  are  left  36  hr.  or  longer/  The  concrete  is  mixed  1:2:5; 
poor  rock  from  the  mine  is  used,  crushed  in  rolls  to  pass  2  in.  and  not 
screened  or  cleaned. 

Concrete  Stringers  in  Steep  Inclines. — The  installation  of  a  concrete 
skiproad  in  a  steep  incline  is  a  much  more  serious  problem  than  a  similar 
installation  in  a  flat  incline.  The  concrete  stringer  itself  must  be  firmly 
anchored  to  the  foot-wall  and  there  is  a  constant  tendency  for  the  rails 
to  creep  down  the  shaft. 

In  the  Copper  Range  shafts,  which  dip  at  an  angle  of  70°,  concrete 
stringers  of  the  Ahmeek  type  were  tried  and  found  unsuitable.  The 
hammer  of  the  skips  is  increased  by  operating  at  a  steep  angle,  since  they 
swing  more  on  the  rope  and  ride  less  smoothly.  As  a  result,  the  nuts 
loosened  on  the  bolts,  which  held  the  rail  to  the  concrete  and  an  elliptical 
hole  was  soon  worn  by  the  bolt  in  the  concrete.  Inspection  of  a  70° 
shaft  is  difficult  and  it  was  necessary  to  devise  some  method  of  holding 
the  rails,  which  could  be  depended  on  for  at  least  a  week  at  a  time,  until 
the  Sunday  inspection  took  place. 

The  system  illustrated  in  Fig.  116  was  originated.  Instead  of  being 
laid  directly  on  the  concrete  or  on  wooden  crossties,  the  rail  is  spiked  to  a 
continuous  6  X  10-in.  wooden  stringer  lying  longitudinally  in  the  concrete 

base  and  occupying  the  upper,  inner  corner  of  it.     The  rails  are  notched 
10 


146 


DETAILS  OF  PRACTICAL  MINING 


in  three  places  on  each  side  of  a  30-ft.  length  to  receive  the  spikes,  which 
are  thus  better  able  to  resist  motion  down  the  shaft.  A  cast-iron  brace 
is  spiked  against  the  outside  of  each  rail  end  to  prevent  spreading,  as 
shown  at  B.  The  wood  stringers  are  bolted  to  the  concrete  at  about  8- 
ft.  intervals.  Access  to  the  bottoms  of  the  bolts  is  had  through  3X4- 
in.  galvanized-iron  boxes,  which  are  set  in  the  concrete,  but  do  not  extend 
through  it.  The  bolt  is  carried  through  a  tube  and  is  countersunk  at 
the  upper  end,  the  countersunk  hole  being  covered  by  the  base  of  the  rail 
so  that  the  bolt  tops  cannot  be  broken  off. 

The  concrete  is  held  to  the  foot- wall  by  anchorages,  as  shown  at  A. 
These  are  put  in  about  every  25  ft.     They  consist  each  of  two  pairs  of 


SIDE   ELEVATION 

~^> 

SECTION   A-A' 
FIG.    115. SUPPORTING  STRINGER  FORMS  IN  SHAFT. 

eye-pins  set  in  10-in.  holes  drilled  in  the  foot-wall  and  held  by  the  concrete 
cast  around  them.  The  lower  pins  are  fastened  to  the  upper  by  bolts 
and  to  increase  the  bond,  four  short  pieces  of  drill  steel  run  across. 

The  concrete  is  cast  flush  with  the  top  and  side  of  the  wood  stringers, 
is  continued  to  the  wall  or  the  divider  in  the  case  of  the  outside  stringers 
and  poured  as  one  block  for  the  adjacent  stringers  of  the  two  skip  ways. 
This  is  in  order  to  leave  as  little  opportunity  as  possible  for  a  rock  to 
lodge  and  derail  the  skip. 

In  constructing  the  skiproads,  the  foot- wall  is  cleaned  and  2  X  6-in. 
crosspieces  C  fastened  to  the  dividers,  are.set  to  grade  by  the  surveyor. 
The  wood  stringers  are  laid  in  the  proper  position  on  these,  the  bolts  and 


SHAFTS  AND  RAISES 


147 


galvanized-iron  boxes  set  in,  and  the  forms  built  up  of  2-in.  planks.  The 
1:2:6  concrete  is  mixed  at  the  bottom  station  of  a  200-ft.  lift  and  hoisted 
in  a  bucket  to  the  shoveling  plat  from  which  it  is  transferred  to  the 
forms.  This  interferes  less  with  mining  operations. 


CROSS-SECTION  OF  SHAFT  ON  LINE    E-F 
FIG.    116. ANCHOR  FOR  STEEPLY  INCLINED  CONCRETE  SKIPWAY. 

Cushion  Blocks  on  Concrete  Skiproads  (By  R.  B.  Wallace)  .—When 
concrete  stringers  were  first  used  for  inclined  skipways,  the  rails  were 
laid  directly  on  the  concrete.  It  was  found  that  this  introduced  con- 
siderable jarring  into  the  operation  of  the  skips,  with  the  result  that  the 


148 


DETAILS  OF  PRACTICAL  MINING 


skip  repair  bill  began  to  mount.  To  remedy  this,  it  was  found  necessary 
to  introduce  a  cushion  between  the  rails  and  the  concrete.  A  convenient 
method  of  doing  this  is  illustrated  in  Fig.  117.  In  1  is  shown  the  posi- 
tion of  the  skip  and  the  stringers  in  the  shaft;  in  2  and  3,  the  details  of 
the  arrangement.  Wooden  crosspieces  A,  2  X  4  in.  or  larger,  are  laid 
in  the  concrete,  projecting  slightly  above  it,  and  the  rails  bolted  to  them. 
An  opening  B  through  the  stringer  directly  below  gives  access  to  the  bolts 
so  that  the  blocks  are  readily  renewable.  If  the  concrete  is  already  laid, 
the  desired  cushioning  can  be  had  by  introducing  %-in.  pieces  of  wood 
under  the  rails,  where  they  are  bolted  to  the  concrete. 


FIG.    117. WOODEN  TIES  IN  CONCRETE  STRINGERS. 


STATIONS 

Cutting  Station  and  Pocket  in  Ore  (By  L.  D.  Davenport). — In  pre- 
paring for  the  cutting  of  a  station  and  pocket  in  an  orebody  on  the  Mesabi 
range,  lines  for  two  small  drifts  are  set  on  the  wall  plates  1  ft.  inside  of  the 
studdles.  The  procedure  is  shown  in  Fig.  118.  Two  5  X  7-ft.  drifts 
are  started  on  these  lines,  and  at  the  same  time,  a  small  raise  is  started 
at  a  distance  of  20  ft.  below  these  drifts.  A  temporary  chute  is  built  at 
the  bottom  to  direct  the  ore  into  the  bucket  in  the  shaft.  This  raise  runs 
up  along  the  shaft,  and  as  the  blocking  and  wedges  are  encountered,  they 
are  removed,  and  the  lagging  is  nailed  in  place  against  the  wall  plates. 


SHAFTS  AND  RAISES 


149 


The  drifts  run  in  16  ft.  from  the  shaft,  and  when  the  raise  is  up  on  a  level 
with  their  bottom,  holes  are  knocked  through.  This  raise  is  used  as  a 
chute  while  the  station  and  pocket  are  being  cut.  When  the  drifts  are 
in  16  ft.  from  the  outside  of  the  shaft,  sills  are  laid  perpendicular  to  the 
wall  plates  with  the  ends  butting  against  the  studdles.  The  tops  of  the 
sills  are  made  flush  with  the  top  of  the  wall  plate  and  the  sills  wedged 
tight  against  the  shaft.  The  backs  of  the  drifts  are  taken  up  to  about 
15  ft.  to  allow  caps  to  be  put  in  place.  There  are  four  18-in.  posts  11 
ft.  long  put  under  each  cap.  The  caps  are  2  to  2J^  ft.  in  diameter,  and 
10  ft.  between  the  shoulders.  The  shoulders  are  cut  in  about  2  in. 


i-ffa/se<f')c4-' 
Section  A-B 


>&3p 


->jj'k---/0'— >ij'<- 

U f&'—-*\ 


WallP/qte. 


Ladd?r-Way 


&*7 


j Round  Timber 


NOT£:-Pooffet  lined 

with  3"p/ank  and 
%  iron  sheeting 


Elevation 


FIG.       118. CUTTING       AND        TIMBERING       A 

STATION  AND  POCKET  IN  SOFT  IRON  ORE. 


J®-JL_ 
Section   G-D 

The  posts  next  to  the  shaft  are  placed  against  the  studdles,  and  those 
at  the  further  end  are  wedged  in  place.  Each  cap  is  also  wedged  against 
the  shaft.  To  put  the  20-ft.  lagging  in  place  (12-in.  round  timber),  a 
cut  is  made  about  2  ft.  higher  than  the  caps,  and  run  in  about  8  ft.  from 
the  shaft.  Small  poles  are  placed  parallel  to  the  caps,  with  one  end  resting 
on  the  wall  plate  and  the  other  in  a  hitch  cut  for  that  purpose.  These 
poles  catch  up  the  back  while  the  lagging  is  being  put  in  place.  The  ore 
in  the  upper  part  of  the  station  is  worked  off  and  a  small  drift  is  started 
to  allow  the  20-ft.  lagging  to  be  placed.  Two  thicknesses  of  boards  are 
placed  over  the  lagging,  with  the  joints  broken,  and  the  back  is  blocked 


150  DETAILS  OF  PRACTICAL  MINING 

up  above  the  boards.  The  remainder  of  the  upper  part  of  the  station  is 
taken  out,  and  the  rest  of  the  20-ft.  lagging  is  placed  and  boarded  up. 
Poles  are  used  as  before  to  catch  up  the  back,  one  end  resting  on  the 
lagging  already  in  place  and  the  other  in  a  hitch.  This  20-ft.  lagging, 
8  or  10  pieces,  is  equally  spaced  and  small  blocks  are  used  to  keep  the 
pieces  apart.  The  lower  part  of  the  station  is  then  taken  out,  and  a  third 
sill  is  placed  between  the  others  at  the  ladderway  divider.  A  "taking- 
up  set"  is  placed  on  this  sill.  The  sills  are  2-ft.  timber  hewed  flat  on 
two  sides,  and  the  taking-up  set  is  14  X  14-in.  square  timber. 

The  pocket  is  then  cut  down  next  to  the  shaft,  and  posts  are  set  under 
the  sills  to  stand  against  the  studdles.  These  posts  are  set  in  hitches 
about  2  ft.  below  where  the  bottom  of  the  finished  pocket  will  come. 
The  pocket  is  next  cut  back,  and  other  posts  are  placed  against  the  first, 
under  the  sills.  These  posts  are  wedged  tight  into  place  and  a  spreader 
or  cross-sill  6  X  12  in.  is  placed  between  the  16-ft.  sills  and  against  the 
wall  plate  to  keep  the  16-ft.  sills  apart.  Another  spreader  12  X  12  in. 
is  placed  at  the  other  end  of  the  16-ft.  sills  and  four  more  cross-sills  are 
placed  between.  Two  of  these  support  the  rails  and  are  let  into  the  16-ft. 
sills.  The  four  cross-sills  are  16  X  16-in.  square  timber.  The  two  wall 
plates  in  front  of  the  station  are  cut  off  against  the  studdles  and  raised 
up  even  with  the  caps.  The  pocket  is  lined  with  3-in.  plank  and  %-in. 
sheet  iron.  Quarter-pans  are  placed  in  the  skipways. 

Underground  Crushing  and  Loading  Arrangements  (By  Albert  E. 
Hall). — In  order  to  facilitate  hoisting  and  avert  delays  in  tramming  at 
the  Creighton  mine,  Ontario,  a  change  was  made  from  the  system  of  dump- 
ing from  the  cars  into  the  skips  to  that  of  dumping  into  a  pocket.  As  the 
muck  at  Creighton  comes  through  the  chutes  in  large  pieces,  a  pocket 
previously  tried  proved  unsuccessful,  since  after  drawing  the  muck  from 
the  chutes  it  would  block  in  the  skip-loading  chutes.  For  this  reason, 
and  also  because  the  rockhouse  crushers  could  not  handle  the  large  mate- 
rial, making  blasting  and  long  stops  necessary  in  the  rockhouse,  an  under- 
ground crusher  was  installed.  A  separate  pocket  is  provided  for  rock, 
which  is  smaller  than  the  ore  pocket.  When  the  rock  pocket  is  filled, 
the  regular  hoisting  of  ore  is  interrupted  and  the  pocket  emptied.  The 
only  change  necessary  is  the  opening  of  the  rock  dump  in  the  headframe, 
which  is  done  in  a  few  minutes  by  the  surface  skiptender  when  the  signal 
for  hoisting  rock  is  rung.  Tramming  of  ore  goes  on  just  the  same  while 
rock  is  being  sent  up. 

All  ore  is  hoisted  from  the  large  pocket  on  the  lowest  level.  The 
shaft  has  four  compartments,  but  only  two  of  these  are  used  for  hoisting 
ore,  and  the  two  skips  work  in  balance.  To  get  the  ore  from  the  levels 
above,  a  large  raise,  known  as  the  ore  pass,  was  put  up.  At  the  bottom 
of  this  is  a  heavily  constructed  chute  with  a  gate  consisting  of  inclined 


SHAFTS  AND  RAISES 


151 


rails  on  each  post  and  a  cross-timber.  The  chute  feeds  to  a  10-in. 
grizzly,  which  in  turn  delivers  to  a  chute  at  right  angles  to  itself.  This 
chute  feeds  the  crusher,  and  on  the  side  opposite  the  chute  grizzly  there 
is  another  grizzly,  also  10-in.,  to  take  the  muck  from  the  cars  on  the  leveL 
A  plan  of  the  arrangements  and  a  vertical  section  are  shown  in  Fig.  119. 
The  construction  is  heavy,  but  the  ore  to  be  handled  is  very  heavy,  being 


Ore  Pockets 


Rock  Pocket  _ 
Cap  46  fans' 
'"Feeding  Floor 
•- 


4-fon  Skip, 


FIG.  119. ARRANGEMENT  OF  UNDERGROUND  STATION,  CRUSHER  AND  POCKET. 

for  the  most  part  pyrrhotite  mixed  with  a  little  chalcopyrite  and  a  small 
quantity  of  pentlandite.  In  addition  to  this,  it  is  very  coarse.  The 
grizzlies  and  crusher  chute  have  little  inclination,  but  the  material  strikes 
them  with  considerable  velocity  and  retains  enough  momentum  to  carry 
it  to  the  crusher.  Were  they  any  steeper,  the  crusher  would  be  blocked 
frequently. 

The  pocket  holds  about  400  tons  and  the  ore  pass  will  hold  about 


152 


DET4ILS  OF  PRACTICAL  MINING 


750  tons,  so  together  they  have  a  considerable  storage  capacity.  The 
pocket  is  provided  with  a  hand-operated  gate  of  the  arc  type,  with  the 
convex  side  toward  the  muck.  It  moves  up  to  allow  the  flow  of  muck 
into  the  loading  pocket.  The  skips  hold  4  tons  and  so  do  the  loading 
pockets.  The  gate  of  the  loading  pocket  is  operated  from  the  same 
floor  as  the  gate  of  the  main  pocket  by  means  of  a  pilot  wheel  and  chain 
and  sprocket.  The  front  of  the  skip  is  made  lower  than  the  other  three 
sides  to  facilitate  even  loading,  and  a  depression  in  the  rail  serves  the 
double  purpose  of  acting  as  a  skip  chair  and  of  giving  the  skip  a  steeper 
inclination,  thus  making  more  complete  loading  possible.  A  block 
with  rail  to  fit  can  be  swung  into  the  chair  when  it  is  desired  to  take  the 
skip  to  the  levels  being  developed  below.  The  loading  pocket  is  built 


Water  line  to 
bearings  and 
pitman 


FIG.    120. — ARRANGEMENT  OF  CRUSHER  AND  BIN. 

of  boiler  plate  and  was  constructed  on  the  surface,  taken  down  in  one 
piece  and  put  into  place. 

The  arrangement  of  the  crusher  is  seen  in  Fig.  120.  It  is  a  Farrel 
crusher  of  the  jaw  type.  Two  heavy  18-in.  I-beams  run  across  the 
pocket  and  are  cemented  into  hitches,  giving  a  firm  foundation  for  the 
crusher.  All  the  timbering  in  the  pocket  to  support  the  grizzlies  and 
crusher  chute  is  14  X  14  in.,  and  is  protected  from  wear  by  boiler  plate. 
The  crusher  is  42  X  30  in.,  and  is  set  to  deliver  10-in.  material.  Two 
100-hp.  motors  are  needed  to  run  it.  No  oil  is  used  in  the  operation  of 
the  crusher,  a  water  pipe  having  been  provided  with  connection  to  each 
bearing  and  to  the  pitman  Grease  cups  are  used  in  addition. 

Once  in  a  while  a  large  boulder  will  get  wedged  on  top  of  the  crusher 
jaws,  and  then  an  air-lift  provided  with  a  chain  and  a  pair  of  ice  tongs, 


SHAFTS  AND  RAISES 


153 


154  DETAILS  OF  PRACTICAL  MINING 

as  shown,  proves  a  great  time  saver.  A  large  piece  can  be  swung  to  fit 
the  opening  in  a  short  time,  whereas  it  would  be  impossible  to  bar  it 
through  and  blasting  means  a  great  loss  of  time,  since  in  addition  to  the 
preparation  of  the  powder,  etc.,  all  the  electric  lights  must  be  taken  out, 
and  even  then  the  wires  may  be  injured.  If  the  piece  is  very  large, 
enough  powder  to  break  it  cannot  be  used  without  danger  of  injuring 
the  crusher.  The  capacity  of  the  crusher  has  never  really  been  tested, 
as  it  is  much  greater  than  that  of  the  hoist. 

Debris  Hoppers  under  Hoisting  Compartments  (Coal  Age). — The 
main  shaft  of  the  Bunsen  Coal  Co.,  of  Danville,  111.,  contains  two  hoisting 
compartments.  The  shaft  is  vertical,  of  rectangular  section,  20  ft.  2  in.  by 
11  ft.,  204  ft.  from  collar  to  bottom  level,  with  a  21-ft.  sump  below  this. 
The  hoisting  compartments  terminate  below  in  a  horizontal  concrete 
and  steel  partition,  constructed  as  shown  in  Fig.  121.  This  is  in  the  form 
of  a  double  hopper  and  below  it  sufficient  room  is  left  to  permit  a  standard 
car  to  be  run  in.  A  heavy  steel  sliding  gate  at  the  bottom  of  each  hop- 
per is  operated  by  means  of  a  chain  and  wheel  at  the  side  of  the  sump. 
By  this  means  the  accumulated  droppings  from  hoisting  operations  can 
be  run  out  as  desired  into  a  car.  When  a  car  is  filled  it  is  pulled  by  motor 
through  a  concrete-lined  tunnel  on  a  sharp  incline  up  to  the  haulage  road. 
The  walls  and  floor  of  the  sump  are  of  concrete  12  in.  thick.  At  the  low 
end  of  the  sump  bottom,  extending  across  the  full  width  of  the  shaft, 
is  a  well  4  ft.  wide  which  catches  all  seepage  water  and  provides  ample 
room  for  a  pump-suction  line. 

Spillage  and  Sinking  Pocket  (By  Albert  E.  Hall). — Where  skips  are 
being  loaded,  either  direct  from  cars  or  from  a  pocket,  there  is  always 
some  spillage.  When  work  is  going  on  below  the  loading  point,  it  is 
necessary  to  keep  this  spilled  material  from  falling  on  those  below,  and  a 
pentice  or  bulkhead  is  often  used  for  this  purpose.  If,  however,  the 
skips  must  make  trips  to  the  lower  workings,  the  labor  of  removing  and 
replacing  a  pentice  causes  loss  of  time.  Even  where  the  skips  do  not 
make  trips  lower  than  the  loading  point,  the  material  spilled  in  loading 
has  to  be  cleaned  up  at  intervals,  which  is  slow  and  costly  work. 

The  pocket  shown  in  Fig.  122  serves  the  double  purpose  of  catching 
the  spillage  from  the  loading  pocket  and  also  of  acting  as  a  pocket  for  the 
material  hoisted  from  the  shaft  bottom  during  the  sinking.  The  shaft  in 
question  is  inclined  at  47°  and  has  four  compartments,  a  ladderway,  two 
skip  compartments  and  a  cage  compartment.  The  cage  runs  to  the  sixth 
level,  so  that  the  cage  compartment  is  clear  below  this  point.  The  skips 
run  to  the  seventh  level,  now  the  lowest  level;  below  this  point  the  shaft 
is  being  sunk.  The  loading  station  lies  between  the  sixth  and  seventh 
levels.  Fig.  122  shows  the  general  arrangement. 

A  drift  was  run  in  behind  the  shaft  on  the  foot-wall  side  and  a  pocket 


SHAFTS  AND  RAISES 


155 


raised  to  the  shaft  just  below  the  loading  pocket.  This  was  divided  into 
three  parts  and  chutes  were  built  in  the  drift  to  correspond  to  these  divi- 
sions. The  center  chute  catches  the  ore  spilled  while  loading  the  skips 
above.  This  is  drawn  from  the  chute  and  trammed  around  to  the  pocket 
on  the  seventh  level.  The  other  two  chutes  in  the  drift  handle  the  rock 
from  sinking.  Two  air  hoists  are  used  to  hoist  this  rock  to  the  pocket. 
Just  above  the  spillage  pocket,  sheaves  were  set,  one  in  the  cage  com- 
partment and  the  other  in  the  ladderway.  The  setting  of  the  last  was 
made  possible  by  moving  the  ladder  as  near  as  possible  to  the  wall.  The 
rock  drawn  through  the  chutes  is  trammed  around  to  the  pocket  on  the 
seventh  level.  No  extra  labor  is  necessary  with  this  arrangement.  One 
hoistman  handles  both  hoists  and  the  buckets  dump  automatically. 


Rock    Ore    Rock 


Chutes  at  Bottom  of 
Spillage  and  Sinking  Pocket 


Ye  Pocket 

"<kip- Loading 
Station 


Level 
Nation 


kip-  Loading 
iaiion  from 
eve/s  above 


op  of  Spillage 
^nd  Sinkmq 


ump  and 
'  :mp  Siaiion 


'Spillage  and 
linking  Pocket 


Elevation 


Plan 


FIG.    122. PLAN  SHOWING  ARRANGEMENTS  FOR  SINKING  AND  SPILLAGE    POCKETS. 


Two  men  handle  all  rock  and  ore  coming  through  the  chutes  and  tram 
it  out. 

Concrete  Hoisting  Pocket  (Bulletin,  American  Institute  of  Mining 
Engineers). — Fig.  123  represents  a  concrete-lined  storage  and  loading 
pocket  of  the  Sacramento  shaft,  the  principal  hoisting  shaft  of  the  Copper 
Queen  company.  It  is  believed  that  the  elimination  of  upkeep  cost  on 
the  concrete  lining  will  more  than  compensate  for  its  increased  first  cost 
over  a  wood  lining.  Furthermore,  the  shape  of  the  pocket  and  the  smooth 
surface  make  the  lining  particularly  adaptable  for  handling  the  wet 
sticky  aluminous  ores,  for  which  purpose  it  was  installed.  The  pocket 
starts  with  an  elliptical  bell-mouth  and  tapers  to  a  3J^-ft.  cylindrical 
chimney.  This  enlarges  to  a  circular  pocket  14  ft.  in  diameter  and  about 
30  ft.  high.  The  capacity  of  this,  the  pocket  proper,  is  52,000  cu.  ft.  or 


156 


DETAILS  OF  PRACTICAL  MINING 


260  tons.  It  has  a  conical  bottom  with  a  6-ft.  opening  which  feeds  to  a 
small  pocket,  which  in  turn  supplies  the  measuring  pocket.  From  one  of 
the  shaft  compartments  a  drift  runs  around  to  a  peep-hole  into  the  pocket 
where  the  cylindrical  chute  widens  to  the  pocket  proper.  The  slanting 
bottoms  at  various  points  in  the  pocket  are  covered  with  rails  where  they 
are  subject  to  the  impact  of  falling  ore.  The  concrete  lining  is  rein- 
forced in  some  places. 


FIG.    123. SECTION  OF  NEW  CONCRETE-LINED  SKIP  POCKET  AND  OLD  TIMBERED  POCKET. 

Concrete  Shaft  Station,  Wolverine  Mine  (By  Claude  T.  Rice). — At 
the  21st  level  of  the  Wolverine  No.  4  shaft,  which  is  sunk  in  the  foot-wall, 
leaving  a  brow  of  rock  between  the  station  and  the  lode,  the  ground  be- 
came heavy  over  the  station  and  caused  much  trouble.  It  was  necessary 
to  retimber  the  shaft  frequently,  as  timbers%  did  not  last  longer  than  6 
or  8  years,  failing  by  decay  alone  in  that  time.  Whenever  it  was 
necessary  to  retimber,  it  was  also  necessary  to  remove  much  of  the  ground, 
which  caused  a  repeated  enlarging  of  the  arch  over  the  station.  In  an 
attempt  to  overcome  this  difficulty,  reinforced  concrete  was  adopted 


SHAFTS  AND  RAISES 


157 


and  the  station  which  was  put  in  has  now  stood  for  over  a  year,  with  no 
sign  of  failure  in  the  concrete. 

The  station  is  illustrated  in  Fig.  124.  It  will  be  observed  that  there 
are  two  heavy  tongues  of  ground,  one  between  the  crosscut  and  the  vein 
and  the  other  between  the  floor  of  the  crosscut  and  the  roof  of  the  shaft. 
Before  the  upper  one  could  be  supported  by  concrete  in  the  crosscut,  it 
was  necessary  to  place  reinforced  pillars  under  the  lower  one.  Unless 


SECT i ON  BETWEE 

SECTION  ArK  TRACKS 

A 


FIG.    124. CONCRETE     SUPPORTS     FOR     A    STATION    IN     HEAVY     GROUND. 

these  two  tongues  were  firmly  held  in  place,  there  would  be  a  tendency  for 
the  whole  piece  of  ground  to  slide  down  the  shaft. 

For  these  concrete  pillars  a  mixture  of  about  1:2:6  or  7  was  used, 
reinforced  by  such  suitable  iron  scrap  as  lay  about  the  mine,  old  rails 
being  the  most  available.  There  are,  however,  two  objections  to  the 
use  of  scrap  for  reinforcement.  It  should  not  be  rusty  or  the  bond  be- 
tween it  and  the  concrete  will  be  defective;  and  furthermore,  it  is  neces- 
sary to  watch  the  workmen  closely  to  insure  that  the  reinforcement  will 


158  DETAILS  OF  PRACTICAL  MINING 

be  put  in  properly  and  in  the  desired  quantity.  Strands  of  old  hoisting 
cable  serve  admirably. 

Another  method  of  reinforcing  pillars  is  to  use  made-up  reinforcement 
forms,  which  can  be  built  into  columns  at  the  surface  or  nailed  to  the 
forms  before  the  concrete  is -poured.  Triangular-mesh  reinforcement 
is  handy,  owing  to  the  fact  that  it  is  hinged  at  each  of  its  main  members. 
Expanded  metal  is  also  good,  but  Hy-Rib,  although  it  saves  the  cost  of 
forms,  is  too  expensive  to  use  underground.  Mr.  Hartman,  the  company 
engineer,  prefers  triangular-mesh  reinforcement;  he  uses  style  42,  which  is 
4-in.  mesh  material,  folding  nicely  into  reinforcing  columns  for  the  sizes 
of  posts  and  pillars  generally  required  in  mine  work.  He  has  evolved 
standard  forms  that  can  be  made  up  by  the  blacksmiths  during  spare 
time.  For  instance,  triangular-mesh  of  the  style  mentioned,  is  pur- 
chased in  the  so-called  30-in.  rolls,  and  can  easily  be  made  into  columns 
2-mesh,  or  8  in.  wide,  by  5-mesh,  or  20  in.  deep,  by  wiring  together  two 
lengths  of  the  reinforcement.  Such  a  reinforcing  column  as  this  is 
stiffened  by  means  of  wire  lacing  running  both  crosswise  and  diagonally 
through  it.  It  is  possible  for  two  men  to  make  up  ten  8-ft.  columns  of 
this  kind  in  2  hr. 

In  1  is  seen  the  triangular-mesh  reinforcement.  This  is  put  in 
with  its  narrower  side  down,  and  is  centered  in  the  form.  The  concrete, 
which  has  been  mixed  usually  on  the  level  above  and  slid  down  the  shaft  in 
'troughs  to  the  platform,  is  then  shoveled  into  the  form,  the  sides  of  the 
latter  built  up  and  more  reinforcement  columns  put  in  as  the  concrete 
rises.  To  guard  against  a  plane  of  weakness  developing  in  the  finished 
pillar,  the  reinforcing  columns  are  wired  together.  The  work  of  shoveling 
the  concrete  into  the  forms  and  of  tamping,  is  made  easier  by  placing 
the  reinforcement  in  the  pillars  crosswise  instead  of  on  end.  If  desired, 
the  concrete  pillars  can  be  reinforced  with  rails  and  %-in.  strands  of 
IJ^-in.  discarded  hoisting  cable.  In  this  case  the  old  mine  rails  are 
placed  at  right  angles  to  the  plane  of  the  shaft  at  intervals  of  about  3  ft. 
and  the  %-in.  strands  of  rope  thrown  into  the  forms  in  sets  of  three  not 
over  12  in.  apart  vertically.  The  rails  must  not  touch  the  ground  or 
they  are  likely  to  take  more  than  their  share  of  the  weight  and  crack  the 
concrete.  Before  any  of  these  pillars  are  put  in,  the  loose  rock  is  picked 
off  the  foot-wall  and  the  ground  washed  down  so  as  to  insure  a  good  tight 
bond  between  the  concrete  and  the  solid  rock  of  the  foot-wall. 

The  skip  tracks  at  the  Wolverine  mine  are  close  together,  the  man  way 
being  carried  along  the  side  of  the  shaft  instead  of  in  the  center  as  is  the 
practice  in  some  of  the  Lake  Superior  incline  shafts.  For  this  reason, 
there  is  room  for  pillars  only  12  in.  wide,  as  they  must  be  put  in  without 
interfering  with  the  hoisting.  On  the  side  next  the  manway,  the  pillar 
is  made  somewhat  wider. 


SHAFTS  AND  RAISES  159 

Resting  on  these  pillars  and  the  foot-wall,  the  floor  beams  of  the 
station  are  put  in.  To  insure  that  they  will  not  be  injured  by  the  skip's 
catching  on  them,  they  are  made  12.  X  22  in.  in  cross-section.  The  gen- 
eral manner  of  reinforcing  these  beams  is  shown  in  3.  The  upper  part  is 
reinforced  by  two  mine  rails  and  five  pieces  of  old  IJ^-m.  hoisting 
cable  are  used  in  the  bottom.  Three  of  the  ropes  are  turned  up  to  an 
angle  of  45°  near  their  ends,  and  when  passing  over  a  support,  in  order  to 
help  the  concrete  in  resisting  shearing  stresses.  To  increase  the  bond 
between  the  concrete  and  the  ropes,  the  latter  are  allowed  to  fray  at  the 
ends.  One  of  these  beams  lies  between  the  two  skip  compartments,  one 
between  the  manway  and  the  adjacent  skip  compartment,  and  the  other 
next  the  wall  of  the  outside  skip  compartment. 

The  columns  that  support  the  roof  beams  are  set  over  the  pillars  in  the 
shaft.  They  are  12  X  18  in.  in  cross-section  and  are  reinforced  with 
triangular-mesh  reinforcement,  style  42.  The  roof  beams  which  rest  on 
these  columns  are  reinforced  in  a  similar  manner  to  the  floor  beams, 
shown  in  3,  except  that  the  rails  are  omitted.  Transverse  bracing  beams 
are  placed  between  the  roof  beams  at  the  posts.  They  are  12  X  12  in. 
in  cross-section;  and  are  reinforced  by  three  IJ^-in.  ropes,  placed  1  in. 
from  the  under  surface  of  the  beam,  the  two  outside  ropes  being  turned  up 
at  an  angle  of  45°  at  the  posts  and  ends  to  resist  shearing  stresses. 

This  whole  structure  is  poured  in  place  and  care  is  taken  to  secure  a 
good  bond  between  the  different  members.  A  mixture  of  1:2:4  is 
.used,  the  rock  being  trap  from  the  mine.  It  is  crushed  in  rolls  to  2-in. 
size  and  used  without  screening.  The  reinforcement  is  placed  in  the 
beams  and  pillars  so  that  1  per  cent,  of  the  beam  area  will  be  steel. 
Where  wire  rope  is  used,  it  is  assumed  to  have  half  the  strength  of  a  bar 
of  the  same  diameter  and  proper  allowance  is  made  for  this  in  the  area 
computations  of  the  reinforcement  requirements. 

The  concrete  filling  pieces  are  made  6  X  6  in.  in  section  and  from 
7  to  8  ft.  long,  reinforced  with  six  J^-in.  strands  of  old  hoisting  cable. 
These  filling  pieces,  as  well  as  the  posts,  caps  and  lagging  slabs  used  in  the 
crosscuts  to  the  lode  are  made  in  forms  on  the  surface.  In  all  these  a 
mixture  of  1 : 2 : 4  is  used,  and  they  are  permitted  to  set  and  season  at 
least  a  month  on  the  surface  before  being  sent  into  the  mine.  The  posts 
of  the  drift  sets  are  made  6  X  6  in.  in  cross-section  and  are  6  ft.  long. 
They  are  reinforced  by  four  J^-in.  bars,  which  are  held  in  the  proper 
position  with  regard  to  one  another  by  wrapping  with  J^-in.  rodding. 
The  caps  are  made  6  X  8  in.  in  cross-section  and  6  ft.  long,  reinforced 
with  three  pieces  of  IJ^-in.  cable.  The  lagging  slabs  are  3  X  12  in.  in 
cross-section  and  4  ft.  long.  A  strip  of  triangular-mesh  reinforcement, 
two  meshes  wide,  is  used  in  reinforcing  them. 

The  ground  in  which  these  concrete  sets  are  used  is  heavy,  due  to  the 


160 


DETAILS  OF  PRACTICAL  MINING 


cracking  of  the  brow  between  the  lode  and  the  crosscuts,  which,  as 
originally  driven,  was  considerably  larger  than  at  present.  The  weight, 
however,  is  a  regular  one,  and  not  so  trying  as  that  encountered  in  swelling 
ground.  The  sets  are  not  cracking  to  any  extent,  and  the  lagging  is  stand- 
ing well,  bending  slightly  but  without  showing  even  hairline  cracks. 

Wood,  Steel  and  Concrete  Station  (By  Claude  T.  Rice). — The  Hancock 
No.  2  shaft  was  sunk  vertically  to  a  depth  of   2600  ft.,  using  buckets  to 


Pin 


•p 


CROSS-  SECTION 


VERTICAL  SECTION 


FIG.    125. LAYOUT    OF    HANCOCK     NO.     2 

SHAFT  STATION. 


raise  the  broken  ground  to  the  surface.  At  about  this  depth  the  34th- 
level  station  was  cut,  bins  were  built  and  thereafter  sinking  was  continued, 
the  muck  or  spoil  being  raised  in  buckets  to  the  bins  at  the  34th  level, 
from  which  it  was  afterward  loaded  into  large  skips  and  raised  to  the  sur- 
face. The  shaft  was  sunk  with  five  compartments,  four  for  hoisting  and 
one  for  pipes  and  ladders. 

Weathering  of  the  rock  was  guarded  against  by  concreting  the  sides  of 
the  station  soon  after  it  was  cut.     In  supporting  the  roof  of  the  station 


SHAFTS  AND  RAISES 


161 


no  timber  was  used  that  would  later  have  to  be  replaced,  nor  was  con- 
creting considered  necessary.  Instead,  a  series  of  70-lb.  rails,  placed 
with  their  flanges  downward  so  that  they  could  be  bolted  easily  to  the 
supports,  was  carried  across  the  station  between  the  compartments  of  the 
shaft.  The  ends  of  these  rest  upon  the  concrete  walls,  while  they  are 
supported  at  the  brow  of  the  station  by  rails  coming  up  from  the  floor 
rails.  These  sill  rails,  in  turn,  rest  upon  the  timbers  of  the  shaft  at  their 
middle  and  in  hitches  at  the  ends.  These  lower  rails  carry  the  floor  of 
the  station.  The  details  of  the  station  lining  are  shown  in  Fig.  125,  in 
which  the  different  supports  are  marked  by  letters. 


0      C 

"f" 

- 

^W-Hf 

j2u 

1  -    ' 

•e—0- 

l«  k—  -$".-•-> 

-4~ 

C 

^ 

rr 


-—/(?'- ->1 

FIG.    126. DETAILS  OF  STEEL  SUPPORT  FASTENINGS. 


The  details  of  the  methods  of  fastening  these  rails  together  with  the 
parts  designated  by  the  same  letters  are  illustrated  in  Fig.  126.  The  long 
rails  that  are  used  as  cap  pieces  to  support  the  roof,  as  well  as  the  sill 
rails  that  carry  the  floor  of  the  station,  are  marked  D.  The  sill  rails 
are  put  in  with  the  flanges  upward,  and  the  cap  rails  with  the  flanges  down. 
The  sill  rails  rest  upon  iron  plates  marked  C,  which  are  placed  on  top  of 
the  shaft  timbers,  so  as  to  keep  the  rails  from  cutting  into  the  wood,  while 
on  top  of  the  cap  rails  similar  plates,  also  marked  C,  are  put  in  to  carry 
the  shaft  timbers.  The  post  rails  marked  E  and  E'  in  the  case  of  the  rail 
that  is  put  in  on  the  back  side  of  the  shaft  when  concrete  is  not  considered 
11 


162  DETAILS  OF  PRACTICAL  MINING 

necessary,  spring  from  these  sill  rails  and  are  secured  to  them  by  the  angle 
pieces  A,  which  are  bolted  to  the  flange  of  each  rail.  At  the  top  a  similar 
angle  fastens  the  cap  rail  to  the  posts.  Also  springing  from  the  sill  rails 
is  a  piece  of  8  X  10-in.  timber,  the  studdle  to  which  the  guides  are  fast- 
ened by  lagscrews.  This  guide  studdle  is  fastened  to  the  sill  by  the  plate 
B,  which  extends  up  higher  on  the  timber  than  the  plate  A  does  on  the 
rails.  This  plate  is  bolted  to  the  rail  and  to  the  timber  as  shown  in  the 
illustration.  In  the  flanges  of  the  rails  that  are  used  as  posts  in  the  front 
of  the  station,  bolt  holes  are  drilled  as  shown  in  Fig.  126,  so  that  the 
timbers  that  are  to  serve  as  jambs  for  the  doors  can  be  bolted  to  them,  and 
to  carry  the  partitions  put  in  at  each  compartment  to  prevent  anything 
from  falling  down  the  shaft.  These  partitions  and  doors  are  made  of  2- 
in.  lumber  and  do  not  require  further  description.  Each  door  is  equipped 
with  a  latch. 

In  cutting  the  station,  it  is  the  practice  to  cut  out  only  for  the  stations 
at  first,  and  then  afterward,  working  in  from  the  shaft,  to  break  out  the 
triangular  space  for  the  ore  bins  from  below.  The  posts  of  the  station- 
shaft  sets  are  made  11  ft.  10  in.  long,  while  posts  9  ft.  long  are  put  in  at  the 
bins.  In  timbering  the  shaft  at  the  bin,  a  small  set  is  put  in  in  front  of  the 
shaft  sets.  These  sets  are  3  ft.  wide  in  the  clear,  so  as  to  provide  room 
enough  for  the  men  to  move  about  while  loading  the  skips.  A  bearer  set  is 
put  in  just  below  the  bin,  and  on  these  bearers  are  stood  the  timbers  that 
carry  the  long  posts  in  front  of  the  skip  chutes.  The  cross-timbers  at  the 
bins  are  carried  in  one  piece  clear  across  the  shaft  and  over  the  front  of 
the  bin.  Into  these  divider  timbers,  the  cross-braces  running  in  the 
direction  of  the  wall  plates,  as  well  as  the  posts  or  studdles,  are  dapped. 

This  type  of  station  and  method  of  lining  have  become  standard  for 
the  shaft,  as  it  provides  for  everything  with  a  minimum  of  excavation. 
The  bins  are  fitted  with  doors,  one  on  each  side  of  the  track,  for  the  ore 
is  hauled  to  the  station  in  saddleback  cars,  by  an  electric  locomotive. 
The  doors  on  the  side  away  from  the  station,  where  the  drop  is  small,  are 
opened  first,  so  that  the  ore  dumped  on  that  side  will  slide  down  the  bot- 
tom of  the  chute,  made  of  rails  laid  in  concrete,  and  form  a  cushion  for  the 
ore  on  the  shaft  side  to  strike  upon,  thus  breaking  its  fall. 

Concrete  Station  at  Champion  Mine. — The  stations  of  the  Champion 
mine  sometimes  require  concreting  of  the  back  where  rather  large  areas 
are  exposed.  Such  a  station  is  illustrated  in  Fig.  127  in  plan  and  section. 
The  wood  timbers  here  shown  are  replaced  in  later  stations  by  concrete 
beams  or  pillars.  The  peculiar  shape  shown  in  the  plan  is  rendered 
necessary  in  order  to  provide  for  sinking,  the  hoist  for  that  purpose  being 
situated  at  A  and  a  temporary  turntable  at  B  for  a  temporary  track  C. 
The  permanent  turntables  E  and  the  cradles  D  are  placed  as  illustrated. 
The  man  way  is  covered  with  10-in.  timber  shown  at  7;  a  trap-door  F  sets 


SHAFTS  AND  RAISES 


163 


in  this  and  the  8-in.  air  pipe  G  passes  through  it.  Between  the  skip 
compartments  a  brattice  of  planks  H  is  built,  to  prevent  miners  from  step- 
ping off  the  cage  into  the  empty  compartment. 

The  reinforcement  in  the  concrete  roof  of  the  main  part  of  the  station, 
as  seen  in  the  sections  and  in  the  plan  of  the  roofs,  consists  of 


PIG.    127. PLANS  AND  SECTIONS  OF  CHAMPION  CONCRETE-LINED  STATION. 

rope.  Some  of  this  is  threaded  through  eye-pins  in  the  back,  these  being 
disposed  as  shown.  This  cable  is  drawn  as  tight  as  possible,  and  the  ends 
and  the  crossings  clamped.  Above  it  are  placed  six  pieces  of  the  same 
cable  extending  in  the  direction  of  the  shaft.  The  roof  is  about  18  in. 
thick.  Similar  reinforcement  is  used  for  the  station  sides,  which  are  from 
10  to  18  in.  thick. 


164  DETAILS  OF  PRACTICAL  MINING 

In  section  UV  can  be  seen  an  eye-bolt  J,  in  the  brow  over  the  shaft. 
One  of  these  in  each  skipway  is  used  to  hold  the  blocks  for  unloading 
heavy  timbers.  The  two  supporting  posts  K,  opposite  the  shaft  dividers, 
are  built  of  four  4-in.  angles  in  the  corners,  wrapped  continuously  with 
%-in.  wire  rope,  the  wraps  about  12  in.  apart.  These  posts  are  10  X  24 
in.  The  divider  in  the  shaft,  seen  at  L,  is  of  concrete,  reinforced  with  1^- 
in.  rope  as  shown. 

The  side  extension  of  the  station  has  an  arched  roof  and  includes  eight 
25-lb.  rails  in  its  reinforcement.  These  are  bent  to  the  arch  of  the  station. 
Eye-pins  are  also  set  in  the  rock  and  a  network  of  Ij^-in.  cable  laced 
through  them  over  the  rails,  except  that  where  it  passes  through  the  center 
pins,  it  is  taken  under  the  rails  and  up  through  the  eye-pins  again.  The 
opposite  side  of  the  station  also  has  a  rail  reinforcement  in  the  back  of  the 
drift. 

RAISING 

Scaffolding  in  an  Untimbered  Raise  (By  Frank  C.  Rork). — A  method 
of  scaffolding  applicable  in  driving  an  untimbered  raise  is  shown  in  Fig. 
128.  The  usual  method  is  to  cut  a  stull  the  right  length  and  wedge  it  in;' 
this  is  not  an  easy  thing  to  do,  working  from  a  ladder,  and  more  or  less 
time  is  consumed  in  finding  and  cutting  the  timber,  in  measuring  and  in 
wedging  the  timber  in  place.  By  the  method  here  illustrated,  when  the 
round  is  finished,  four  holes  are  drilled,  two  at  A  and  two  at  B,  near  the 
corners  of  the  raise.  The  depth  of  these  holes  should  be  about  10  in., 
depending  on  the  nature  of  the  rock.  They  should  be  placed  the  height 
of  one  cut  above  C  and  D  and  will  then  be  in  the  proper  position  to  hold 
the  scaffold  after  the  round  is  fired.  The  scaffold  can  be  quickly  erected 
on  two  stulls,  resting  on  four  pieces  of  steel  inserted  in  the  holes.  As  the 
raise  progresses,  the  lower  holes  can  be  used  to  secure  the  ladders  in  the 
manner  illustrated.  The  shallow  holes  can  be  drilled  rapidly  and  easily 
with  all  the  equipment  at  hand  and  the  drill  steel  consumed  would  prob- 
ably be  lost  or  wasted  if  not  thus  utilized. 

Five-hole-cut  Raising  Method  (By  H.  H.  Hodgkinson).— The  five- 
hole-cut  method  here  described  has  proved  to  be  the  best  and  most 
economical  method  for  both  drifting  and  raising  at  the  New  Jersey  Zinc 
Co.'s  mines  at  Franklin  Furnace,  N.  J.,  where  the  ore  and  limestone  as  a 
rule  are  soft.  Although  this  method  necessitates  drilling  more  holes 
than  either  the  draw-  or  the  V-cut  method  used  in  the  West  where  the 
ground  is  hard  and  brittle,  yet  it  can  be  depended  upon  to  break  a  good 
clean  heading  in  either  ore  or  limestone.  These  other  methods  fail  unless 
an  excessive  number  of  holes  are  drilled,  which  takes  more  powder,  for 
due  to  the  soft  nature  of  the  ground  the  holes  when  fired  do  not  break 
the  ground  but  simply  chamber  and  blow  off  a  little  of  the  collars. 


SHAFTS  AND  RAISES 


165 


In  drilling  up  a  round  in  a  raise,  17  holes  are  put  in,  as  shown  in  Fig. 
129,  to  a  depth  of  6  ft.  The  ground  is  easily  drilled,  the  machines  aver- 
aging 14  to  20  ft.  per  hour.  When  the  round  is  fired  a  heading  5  X  5  ft. 
is  broken  with  an  advance  of  not  less  than  5  ft.  This  is  accomplished  in 
an  eight-hour  shift. 

About  92  sticks  of  lX8-in.  50  per  cent,  gelatin  dynamite  are  required 
to  break  a  round.  Hole  No.  2  is  loaded  with  eight  sticks  of  dynamite 


FIG.    128. SCAFFOLD  AND  LADDERS  SUPPORTED  ON  DRILL  STEEL. 

and  fired;  this  breaks  through  the  other  four  cut  holes  Nos.  1,  3,  4  and  5 
as  shown.  Holes  Nos.  6,  7,  8  and  9  are  then  loaded  with  seven  sticks 
each  and  fired  after  the  muck  is  cleaned  out  of  the  space  made  in  firing 
hole  No.  2.  The  remaining  eight  holes  are  loaded  with  seven  sticks  of 
dynamite  each  and  fired.  At  least  two  bags  of  tamping  are  used  in  each 
hole  and  pressed  in  firmly. 

Draining   Watercourses  in  Chutes    (By   Edward   P.   Scallon).— In 
raising,  watercourses  are  frequently  encountered.     If  the  raise  is  to  be 


166 


DETAILS  OF  PRACTICAL  MINING 


used  as  a  chute,  much  delay  and  annoyance  in  the  subsequent  handling 
of  the  product  are  occasioned  by  an  admixture  of  the  water  and  ore  in 
the  chute,  and  in  most  cases  it  is  essential  that  this  condition  be  remedied. 
At  the  Lincoln  mine  of  the  Inter-State  Iron  Co.,  at  Virginia,  Minn.,  the 
form  of  chute  construction  shown  in  the  accompanying  drawing,  Fig.  130, 
is  employed  successfully  to  overcome  the  difficulty.  After  the  raise  is 
driven,  several  6-ft.  drill  holes  are  placed  in  its  side,  so  as  to  cut  the  water- 
bearing strata  transversely  at  different  elevations.  Pipes  are  then  ce- 


t-<- 5 1 


FIG.    129. LAYOUT  OF  HOLES  FOR  FIVE-HOLE-CUT  RAISING. 

mented  into  the  collars  of  these  holes  and  extended,  close  to  the  side  of 
the  raise,  to  the  level  below.  Air  lines  and  any  other  necessary  pipes  are 
placed  along  the  walls,  and  the  entire  raise  is  lined  with  concrete,  cor- 
rugated culvert  pipe  being  used  as  a  form.  All  the  pipes  will  of  course 
be  embedded  in  the  concrete;  the  small  drainage  pipes  from  the  drill 
holes  will  collect  all  the  water  and  carry  it  to  the  level  below.  This  pre- 
vents the  exertion  of  any  water  pressure  on  the  concrete  while  setting  or 
subsequently,  and  also  allows  proceeding  with  the  drainage  of  the  area 
tributary  to  the  raise. 


SHAFTS  AND  RAISES 


167 


By  the  use  of  these  drainage  pipes  it  is  found  at  the  Lincoln  mine 
that  almost  all  watercourses  can  be  sealed  off  with  oakum  and  dry  cement. 
In  this  case,  if  desirable,  a  form  of  plank  chute  providing  protection  to 
the  pipes  and  cement  can  be  substituted  for  the  more  permanent  con- 
crete and  metal-lined  construction  described  above.  The  water  collected 


Broken 

S+ra+a 

Water 

bearing 


Broken  . 
Sfr&fa 

Wafer 
dearina 


FIG.    130. CONCRETE  AND  PIPES  FOK  DRAINING  RAISE. 

in  the  pipes  from  such  a  raise  is  used  to  supply  tanks  feeding  Leyner  drills 
on  the  lower  levels. 

LADDERS 

Wood  and  Iron-pipe  Ladder. — An  economical  and  serviceable  mine 
ladder  may  be  made  of  4  X  4-in.  timbers,  with  rungs  of  1-in.  pipe,  the 


168 


DETAILS  OF  PRACTICAL  MINING 


latter  consisting  of  discarded  pipe  sawed  into  20-iri.  lengths,  Fig.  131. 
The  rungs  are  spaced  1  ft.  apart,  holes  being  bored  through  the  timbers 


FIG.    131. LADDER  OF  4   X  4-IN.    UPRIGHTS  AND  1-IN.  PIPE    RUNGS. 

just  large  enough  to  receive  them.     Small  holes  are  drilled  through  each 
pipe  length,  one  near  each  end,  before  driving  into  the  timbers,  and  when 


««--//*  , 

u 

-\I9*  

4" 

-> 

•T 

ti 

-^ 

FIG.    132. LADDER  OF  3    X  4-IN.    UPRIGHTS  AND    1/2-IN.    STEEL   RUNGS. 

the  rungs  are  in  place  nails  are  inserted  into  these  holes  and  driven  tight. 
This  prevents  the  rungs  from  twisting  or  slipping  sideways  and  holds  the 
ladder  securely  together.  Such  ladders  cost  more  in  the  first  place  than 


SHAFTS  AND  RAISES 


169 


ladders  of  the  same  length  constructed  of  2  X  4-  and  1  X  4-  in.  lumber,  but 
their  cost  may  be  kept  low  by  using  the  better  parts  of  discarded  pipe  and 
having  the  shop  crews  make  up  extra  ladders  during  what  would  other- 
wise be  spare  time,  while  their  great  durability,  which  largely  reduces  the 
repairs  necessitated  by  breakage  and  wear,  makes  it  economical  to  use 
them  instead  of  all-wood  ladders,  especially  in  more  permanent  manways. 
Steel  and  Wood  Ladder  (By  Harold  A.  Linke).  —  In  Fig.  132  is  shown 
a  substantial  and  inexpensive  mine  ladder,  the  sides  of  which  are  con- 
structed of  3  X  4-in.  stuff,  surfaced  two  sides  and  one  edge,  and  the  rungs 
of  -iri.  round  mild  steel.  The  bill  of  material  is  as  follows: 


Two  pieces  3  X  4-in.  by  24-ft.  S2S1E. 

Thirty  feet  %-in.  round  mild  steel,  cut  into  21  rungs 

four  19-in.  lengths,  the  latter  threaded  2  in.  both  ends. 
Eight  ^-in.  cut  washers. 
Eight  %-m.  square  nuts. 


in.  long  and 


After  the  ladder  is  made  and  the  bolts  tightened  it  is  well  to  rivet  the 
ends  of  the  tie  bolts  or  burr  the  exposed  threads  to  prevent  the  nuts  from 
working  off. 

Portable  Steel  Ladder  (By  L.  O.  Kellogg).  —  The  Penn  Iron  Mining 
Co.,  on  the  Menominee  range,  has  adopted  an  all-steel  ladder  for  under- 


FIG.    133. LIGHT    ALL-STEEL  LADDER  OF  PIPE  AND  CHANNEL. 

ground  use.  Fig.  133  shows  the  type  used  in  stopes  and  manways  where 
the  installation  is  more  or  less  temporary.  The  ladder  is  12  ft.  long, 
1  ft.  wide  and  weighs  a  little  under  50  Ib.  The  sides  are  of  1  y±  X  M-in. 
channels  with  the  flanges  inside;  the  rungs  are  of  J^-in.  pipe.  The  ends 
of  the  pipes  are  bent  at  right  angles  in  opposite  directions,  flattened  and 


170 


DETAILS  OF  PRACTICAL  MINING 


riveted  to  the  channels,  the  rivets  being  countersunk  on  the  outside. 
The  ladders  are  of  unusually  light  construction,  but  are  found  to  stand 
up  well  in  service  and  are  extremely  convenient  to  carry  about  and  place 
as  needed.  They  are  found  preferable  to  the  type  first  tried,  built  of 
heavier  channels  and  %-in.  pipe  and  weighing  nearly  twice  as  much. 
For  permanent  installations,  as  in  the  shaft,  a  much  heavier  ladder  is  used, 
built  also  entirely  of  steel. 

Pipe-and -angle  Ladder  (By  Edward  S.  Wiard). — The  details  of  the 
steel  ladders  used  at  the  Capital  mine,  Georgetown,  Colo.,  were  worked 
out  by  the  superintendent,  E.  C.  Bauman.  The  principal  advantages  of 
these  ladders  as  against  wooden  ones  are  lightness,  portability,  greater 


fish  Plate 


Fish  Plate-  n 


-Fish  Plate 
FIG.    134. MINE  LADDER  OF  ANGLE  IRON  AND  PIPE. 

cheapness  in  the  long  run  and  safety.  Fig.  134  shows  the  construction 
and  dimensions.  The  rounds  are  made  of  old  1-in.  or  lj^-in.  pipe.  This 
is  cut  up  into  suitable  lengths,  and  both  ends,  after  heating  in  the  forge, 
are  mashed  flat.  The  flattened  ends  are  then  drilled  and  cold-riveted  to 
the  angle  irons  forming  the  sides  of  the  ladders.  The  ladders  at  the 
Capital  mine  are  made  in  the  10-ft.  lengths,  which  are  easily  handled. 
They  are  held  in  place  in  the  manways  by  ladder  hooks  placed  in  the 
usual  way.  To  hold  the  ladder  away  from  the  wall  plates — if  this  pro- 
cedure is  necessary  to  give  a  good  foothold — blocks  may  be  inserted 
between  the  ladder  and  the  wall,  the  hook  embracing  both  block  and 
ladder.  If  desired,  four  pieces  of  steel  of  the  same  size  and  shape  maybe 


SHAFTS  AND  RAISES  171 

riveted  in  pairs  to  the  ends  of  the  ladder  to  attain  the  same  purpose — that 
of  holding  it  away  from  the  sides  of  the  manways.  As  fast  as  the  ladders 
are  put  into  place  they  are  connected  to  the  lengths  above  or  below  by 
fish-plates  and  bolts,  so  that  each  section  receives  the  support  not  only  of 
its  own  ladder  hooks,  but  of  all  the  others. 

The  weight  and  cost  of  this  ladder  at  the  mine  are  as  follows: 

Weight  r     . 

in  pounds 

Rivets  and  bolts 3                        SO .  30 

Angles 30                          0.83 

Pipe 27  (half  price)    0.50 

Fish-plates 1^                      0. 04 

Total 61 K 

Labor..  . /.  .  0.86 


Total  cost $2. 53 

If  the  pipe  is  considered  worthless  the  cost  will  be  reduced  to  SI. 67. 
The  material  for  wooden  ladders  will  cost  from  one-fourth  to  one-half 
the  steel;  the  labor  cost  will  be  as  much  or  greater.^  The  greater  cost  of 
the  steel  ladders  is  soon  made  up  by  the  longer  life. 

Wood  vs.  Steel  Mine  Ladders  (By  George  E.  Collins). — In  the  Engi- 
neering and  Mining  Journal  of  May  29,  was  a  note  with  sketch  by  my 
friend  E.  S.  Wiard,  about  steel  ladders  used  at  the  Capital  mine,  George- 
town, as  to  which  I  wish  to  suggest  a  word  of  warning.  In  most  mines 
such  ladders  would  be  unsafe.  Moisture  is  apt  to  collect  behind  the 
rungs  where  the  latter  are  riveted  to  the  sides.  This  results  in  rust, 
and  when  the  rivet  has  rusted  through  the  ladders  are  very  dangerous, 
as  the  defect  is  not  visible.  Steel  ladders  should  be  used  only  where 
liability  of  dry  rot  renders  wood  unsuitable;  and  even  then  I  believe  a 
design  in  which  the  pipe  rungs  actually  pass  through  the  sides  would 
be  safer  and  more  generally  preferable.  Even  in  a  dry  mine  there  is 
usually  moisture  enough  to  develop  rust  on  metal  surfaces,  especially 
when  two  such  surfaces  are  in  approximate  but  not  actual  contact. 

In  my  experience,  light  weight  in  ladders  is  ordinarily  a  matter  of 
secondary  importance.  Where  a  length  of  ladder  has  to  be  moved  fre- 
quently, very  light  ladders  will  of  course  be  built.  Ladders  are  intended 
primarily  to  travel  on;  and  next  to  safety,  convenience  in  climbing  is  the 
most  important  requisite.  Pipe  or  other  metal  rungs  are  cold  to  the 
hands,  and  when  wet  and  gritty  cut  the  skin  more  than  wooden  rungs. 
Moreover,  pipe  is  slippery  and  does  not  afford  so  good  a  grip  for  the  feet 
as  wood. 

In  most  places,  wooden  ladders  are  best.  Probably  the  most  gener- 
ally suitable  design,  taking  convenience  and  cost  into  consideration,  is  that 
shown  in  Fig.  135,  where  sides  and  rungs  are  both  made  of  2  X  4  stock, 


172 


DETAILS  OF  PRACTICAL  MINING 


the  rungs  being  inset  1  or  1J^  in.  into  the  sides.  If  neatly  made  of  dry 
lumber,  the  rungs  swell  when  wet,  so  that  they  are  firmly  held  in  the  slots, 
even  if  the  nails  with  which  they  are  originally  secured  should  rust  out. 
Worn  rungs  are  easily  replaced — an  important  consideration,  for  the  neg- 
lect of  which  there  is  no  excuse — and  even  when  a  rung  is  worn  through  or 
broken,  the  pieces  hold  sufficiently  for  safe  travel.  Such  ladders  made  of 
red  spruce,  at  a  high-altitude  mine  in  Colorado,  cost  10J^  cts.  per  foot 
complete  as  against  Mr.  Wiard's  figure  of  25  cts.  per  foot  for  the  steel 
ladders.  Their  life,  apart  from  damage  by  falling  rocks — which  in  my 
experience  is  equally  destructive  to  the  1-  or  l^-in.  pipe — is  very  long, 
sometimes  exceeding  that  of  the  mine  itself. 

Where  the  ladders  are  exposed  to  the  drip  of  acid  water,  I  have  used 
the  form  shown  in  Fig.  136.  Here  the. rungs  are  made  of  2  X  4  or  2  X  5 
lumber,  sawed  on  an  angle  lengthwise,  so  as  to  make  pieces  of  the  section 


12" 


*  Sec-Kon  A~B 
when  Lumber 


Seclion  A~B 

when  Lumber 

is  2V 


FIG.    135.  FIG.    136. 

LIGHT  WOODEN  MINE  LADDERS. 


as  illustrated  1J£  in.  one  side  and  2^  m-  the  other,  when  sawed  from 
2X4  lumber,  or  2J^  in.  and  3^  in.  respectively,  when  sawed  from 
2X6  lumber.  In  either  case,  one  cut  in  the  side  pieces  is  made  at  right 
angles  and  the  other  obliquely,  so  that  the  rungs  are  firmly  held  without 
nails.  Of  course  the  flat  side  of  the  rungs  is  placed  uppermost.  These 
ladders  cost  but  a  trifle  more  than  the  first  mentioned.  Where  there  is 
liability  of  dry  rot,  I  have  used  2X4  lumber  for  the  sides  and  old  pipe 
sawed  into  lengths  for  rungs.  If  the  holes  in  the  sides  are  a  tight  fit,  no 
other  fastening  is  necessary.  I  do  not  know  why  wooden  uprights  last 
so  much  longer  than  rungs  —  to  a  greater  extent  than  the  increased  section 
would  suggest  —  but  such,  in  my  experience,  is  the  fact.  The  sides  might 
be  dipped  in  creosote  or  treated  with  copper  sulphate,  although  I  person- 
ally have  not  tried  either.  Either  preservative  used  on  wooden  rungs, 
would  be  a  nuisance.  The  facility  with  which  the  sides  of  wooden  ladders 
may  be  spiked  to  timbers  or  fastened  to  one  another  by  means  of  cleats  is 


SHAFTS  AND  RAISES 


173 


much  greater  than  that  by  which  steel  ladders  can  be  suitably  fastened  by 
hooks  or  staples.  Of  course  the  advantage  mentioned  by  Mr.  Wiard,  of 
each  section  being  supported  by  the  others,  may  and  usually  does  apply 
to  wooden  ladders  as  well  as  to  those  made  of  steel.  In  the  old  district 
of  Gilpin  County,  ladders  usually  have  sides  of  2  X  4  lumber,  with  rungs 
made  either  of  round  lj^-in.  hardwood  or  of  2  X  2  native  lumber  cham- 
fered at  the  edges  and  turned  down  at  the  ends  to  1%  in.,  which  fit  closely 
into  a  round  hole  of  equal  diameter  in  the  side  pieces.  A  nail  through  the 


C 


c 


<-2'H 


C 


•0155, 


•a* 


FIG.    137. LADDER  OF  ANGLES  WITH  REMOVABLE  RUNGS. 

side  into  the  rungs  at  each  hole  adds  some  further  security.  These  are 
good  ladders  to  climb,  but  are  not  quite  so  safe  as  those  made  of  2  X  4 
slats  nor  so  durable.  They  retail  at  the  rate  of  12  cts.  per  running  foot. 
Slats  made  of  1  X  3  or  1  X  4  are  sometimes  used,  but  are  not  strong 
enough,  and  give  poor  footing.  They  should  be  used  for  movable 
ladders  only. 

Isabella  Knockdown  Iron  Ladder  (By  Leo  H.  P.  Kneip). — The  ladder 
shown  in  Fig.  137  is  one  installed  in  the  new  steel  and  concrete  shaft  of 


174 


DETAILS  OF  PRACTICAL  MINING 


the  Isabella  mine,  at  Palmer,  Mich.,  operated  by  the  Cascade  Mining  Co. 
The  ladder  was  devised  by  Francis  H.  Tippett,  as  a  result  of  a  competi- 
tion promoted  by  the  superintendent,  Thomas  J.  Nicholas.  The  ladder 
uprights  are  2  X  2  X  %Q-in.  angles,  the  rungs  are  %-in.  iron.  The  rungs 
are  inserted  through  %-in.  holes  in  the  angles  and  drop  into  a  taper  slot  cut 
downward  from  the  hole.  A  pair  of  grooves  in  each  end  hold  the  rung  in 
the  flange  against  turning  and  also  brace  the  angles  against  side  motion. 
The  rung  is  locked  in  with  a  swing  lug  having  a  beveled  bottom,  as  shown. 


r/rvn  Hung 
\floodzn  Rung 


FIG.    138. METHOD  OP  HANGING  LADDERS  IN  A  RAISE. 

If  a  rung  should  break,  a  new  one  can  be  inserted  without  taking  down  the 
ladder  or  springing  it.  The  ladder  contains  no  threads,  bolts  or  nuts  and 
can  be  made  without  special  tools  in  any  mine  shop. 

Method  of  Hanging  Ladders. — When  ladders  are  required  only  for 
temporary  use  in  raises  and  millholes  in  the  mines  of  the  Copper  Range 
Company,  in  the  Lake  Superior  country,  it  is  the  custom  to  use  several 
12-ft.  ladders;  the  lower  one  rests  upon  the  ground  while  each  of  the  others 
is  carried  by  %-in.  round-iron,  S-shaped  hooks  from  the  ladder  below,  as 


SHAFTS  AND  RAISES 


175 


shown  in  Fig.  138.  The  ladders  are  made  of  oak  with  2  X  4-in.  legs  and 
rungs  1)^  in.  in  diameter  spaced  1  ft.  apart.  Three  tie-rods  are  used: 
One  at  the  center;  one  below  the  second  rung  from  the  bottom;  and  one 
above  the  second  rung  from  the  top.  The  S  hooks  grip  the  ladders  by 
the  tie-rods  and  the  ladders  overlap  at  the  junction.  It  is  better  to  place 
the  overlap  of  the  lower  ladder  on  top  of  the  upper  one,  provided  they  are 
inclined,  as  they  should  be,  since  that  arrangement  makes  it  easier  for  a 


'  Waff  \[ 

—*\  Treads 


s 


II'- 

Plon 


?io 


Section  trk 
FIG.    139. PLAN  AND  SECTION  OF  STAIRWAY. 


man  coming  down  to  know  when  he  has  reached  a  junction.  A  temporary 
sollar  is  usually  put  in  the  raises  at  intervals  of  every  two  ladders  whenever 
three  or  more  ladders  are  used.  Sprags  are  used  to  present  side  swing. 
The  overlap  is  so  long  that  there  is  no  danger  of  hinging  of  the  ladders  at 
the  junctions. 

Vertical-shaft  Steel  Stairway  (Coal  Age). — The  air  shaft  or  auxiliary 
shaft  of  the  Bunsen  Coal  Co.,  Danville,  111.,  is  divided  into  three  compart- 


176  DETAILS  OF  PRACTICAL  MINING 

ments  and  lined  with  concrete.  One  of  the  compartments,  about  5X11 
ft.,  is  reserved  for  a  manway  and  fitted  with  a  steel  stairway.  The  shaft 
is  vertical,  rectangular,  11  X  25  ft.  inside  lining,  and  about  210  ft.  deep. 
The  stairway,  as  shown  in  Fig.  139,  is  of  zigzag  pattern  and,  together 
with  the  landings,  occupies  a  space  longitudinally  in  the  shaft  for  a  width 
of  5  ft.  6>^  in.  Each  flight  rises  on  a  39°  25'  angle  from  the  horizontal, 
and  is  8  ft.  long.  The  separate  flights,  including  the  landings,  are  sup- 
ported on  8-in.  channels  weighing  llj^  Ib.  per  foot,  placed  crosswise  in 
the  shaft,  which  in  turn  are  supported  at  one  end  on  the  10-in.  I-beam 
dividers,  while  the  other  end  is  secured  in  the  concrete  end  wall  and  has  a 
bearing  of  6  in.  The  channels  are  placed  2  ft.  5J^  in.  from  the  side  walls, 
and  are  spaced  vertically  5  ft.  center  to  center,  alternating  for  each  flight. 
The  stair  stringers  are  J4  m-  thick  by  7  in.  deep.  The  treads  are  Y±  X  11 
in.  by  2  ft.  6  in.,  with  checkered  surfaces,  and  are  supported  on  1%  X 
X  J4-in.  angles,  riveted  to  the  stringers.  The  rise  between  treads  is 
in.  The  landing  plates  are  Y±  in.  by  2  ft.  9  in.  by  5  ft.,  and  are  also 
checkered  on  the  surface.  Three  lugs  of  3%  X  5  X  /^-in.  angle  iron  are 
riveted  to  the  landing  plate  and  fastened  to  the  concrete  wall  by  means 
of  %  X  5-in.  expansion  bolts  well  drawn  up.  The  hand  railings  are  made 
up  of  two  lines  of  lj^-in.  pipe;  the  uprights  are  bolted  to  the  stair  stringers 
and  connected  to  each  line  of  railing.  The  total  weight  per  vertical  foot 
of  stairway  and  landings,  not  including  the  channel  supports,  is  100  Ib. 
The  stairway  is  easy  for  the  men  to  walk  on  and  is  of  economical  design. 


DRIFTING 

General  Methods — Drilling  Rounds — Support  of  Workings 
GENERAL  METHODS 

Driving  the  Sheep  Creek  Tunnel. — The  Sheep  Creek  tunnel  was  driven 
by  the  Alaska-Gastineau  Mining  Co.,  near  Juneau,  Alaska,  to  provide 
ore  transportation  facilities  from  mine  to  mill.  Of  the  total  tunnel 
length,  474  ft.  was  through  slide  rock  and  gravel  near  the  portal,  4009  ft. 
in  greenstone,  4224  ft.  in  slate  and  1085  ft.  in  metagabbro;  the  last  three 
rocks  alternated,  the  stretches  varying  from  a  few  feet  up  to  several 
thousand.  In  general,  the  direction  of  the  tunnel  followed  the  strike  of 
the  formation,  making  it  difficult  to  break  the  rock,  especially  the  hard 
silicified  slate,  where  the  effect  of  the  cleavage  planes  was  marked.  The 
holes  broke  short  and  a  great  many  were  required.  Greenstone  also 
developed  cleavage  planes  in  places,  with  a  similar  result.  When  the 
tunnel  was  in  homogeneous  blocky  greenstone,  the  rate  of  progress  jumped 
to  about  a  foot  per  hour.  In  general,  shallow  rounds  giving  an  average 
advance  of  4  ft.  were  found  most  economical  and  rapid. 

The  tunnel  was  10  ft.  wide  and  8  ft.  high,  with  a  small  ditch  along  one 
side.  Timbering  was  necessary  only  in  the  loose  ground  near  the  portal, 
and  at  this  point  the  section  was  kept  8  X  10  ft.  inside  timbers.  While 
the  total  length  of  tunnel  is  9792.2  ft.,  from  the  solid  rock  face,  where  the 
main  tunnel  started,  to  its  intersection  with  the  crosscut  from  the 
Perseverance  shaft  the  distance  is  8800.5  ft.  The  tunnel  was  driven  for 
single  track  its  entire  length,  with  the  intention  of  widening  out  for  sidings 
later.  The  average  up-grade  from  the  entrance  was  0.65  per  cent. 

The  force  consisted  of  70  men.  Working  on  day  shift  only,  there  was 
a  general  foreman,  a  time-keeper,  a  tool  sharpener,  a  tool-sharpener 
helper,  a  blacksmith,  a  blacksmith  helper,  a  carpenter,  an  electrician,  a 
powderman,  and  an  outside  man.  Two  compressor  men  worked  12-hr, 
shifts  each.  Divided  into  three  shifts,  there  were  3  shift  bosses,  12 
upper-bar  machinemen,  12  lower-bar  machinemen,  18  muckers,  3 
carmen,  3  locomotive  engineers,  3  locomotive  brakemen  and  4  pipe-  and 
trackmen.  The  arrangement  of  shifts  was  unusual.  The  cycle  was  com- 
pleted in  18  instead  of  24  hr.;  during  this  time  each  of  the  three  crews 
into  which  the  force  was  divided  worked  6  hr.  and  rested  12,  so  that 
12  177 


178  DETAILS  OF  PRACTICAL  MINING 

in  each  24  hr.  there  was  8  hr.  of  work  for  each  man.  The  incoming  shift 
would  relieve  the  outgoing  shift  at  the  working  face  and  there  was 
no  intermission  in  the  work  for  the  purpose  of  eating  a  meal;  this  elimi- 
nated the  delay  of  the  meal  time  and  the  slackening  of  work  following 
heavy  eating. 

After  spitting  the  round,  the  men  walked  back  in  the  tunnel  about 
1000  ft.  The  holes  were  counted  and  immediately  after  the  last  lifter 
went  off  the  men  started  toward  the  face  again.  The  fans  being  in  full 
operation  continuously,  no  smoke  was  encountered  until  within  about  60 
ft.  of  the  face.  One  man  then  carried  to  the  breast  a  water  hose,  pre- 
viously connected  to  the  water  line,  and  sprayed  the  muck.  Meanwhile 
the  manifold  was  connected  to  the  air  line  and  the  air  hose  attached 
thereto.  The  top  bar  was  next  brought  up  and  jacked  into  place;  two 
machines  were  placed  on  the  bar,  the  air  hose  connected  as  soon  as  possi- 
ble and  drilling  started.  At  the  beginning  of  tunneling  operations  it  re- 
quired about  30  min.  from  the  time  the  last  lifter  was  fired  until  the  top- 
bar  machines  were  running.  By  the  end  of  the  undertaking  this  took  fre- 
quently only  10  min.  and  seldom  more  than  15.  With  the  top  machines 
in  operation,  the  four  lower-bar  machinemen  started  mucking  out  to  make 
room  for  the  lower  bar.  They  threw  back  to  the  slick  sheet,  from  which 
the  muckers  loaded  into  the  cars.  It  was  usually  possible  to  set  the  lower 
bar  and  finish  drilling  the  lower  holes  by  the  time  the  top  machines  were 
finished,  so  that  all  of  the  machines  were  torn  down  together. 

While  the  machines  were  being  placed  in  position,  mucking  began. 
The  empty  car  was  brought  ahead  and  the  track  cleaned  up  to  the  slick 
sheet.  Of  the  six  muckers,  four  were  .shoveling  continually  and  two 
resting.  The  average  output  of  the  force  was  10  to  12  tons  per  hour. 
On  a  slick  sheet  beside  the  track,  within  50  ft.  of  the  face  at  all  times,  an 
empty  car  was  kept.  Whenever  a  car  was  loaded,  the  carman  took  it 
down  the  track  and  brought  back  the  empty.  There  was  thus  only  a 
fraction  of  a  minute  lost  in  changing  cars.  A  few  hundred  feet  back  from 
the  face  another  slick  sheet  was  maintained  and  when  the  locomotive 
brought  in  a  train  of  empties,  they  were  thrown  off  the  track  on  this 
sheet.  The  loaded  cars  were  run  back  to  this  point,  made  up  into  a  train 
and  hauled  out.  From  this  latter  sheet,  the  empty  cars  were  run  one  at  a 
time  up  to  the  sheet  near  the  face.  The  empty  cars  weighed  about  1100 
Ib.  and  were  handled  by  a  man  using  a  crowbar.  The  sheets  were  kept 
about  the  same  height  as  the  top  of  the  rail  so  that  the  car  required  to  be 
lifted  only  the  height  of  the  flange.  No  switches  were  used  anywhere. 
At  no  time  did  the  removal  of  the  muck  limit  the  speed  of  drifting  or  in- 
terfere with  the  drilling  cycle.  The  steel  plates  used  for  the  slick  sheet 
sidings  were  Y±  X  48  X  140  in.  The  siding  some  distance  from  the  face 
was  48  to  60  ft.  long;  directly  opposite  it  were  Y±  X  22  X  140-in.  sheets, 


DRIFTING  179 

resting  on  planks  down  the  center  of  the  track,  and  also  flush  with  the 
rail  heads. 

After  practically  all  the  muck  was  cleaned  out,  the  shovelers  laid  ties 
to  grade  as  the  tunnel  advanced,  thus  facilitating  the  subsequent  laying 
of  the  rails.  A  25-ft.  false  track  was  advanced  over  the  ends  of  the  rails 
as  necessary,  so  that  the  cars  were  always  next  to  the  muck  pile.  When 
the  advance  permitted  the  insertion  of  a  set  of  rails,  the  foreman  and 
muckers  did  the  work  in  15  to  20  min.,  without  disturbing  the  machine- 
men.  On  the  completion  of  the  round,  shovelers,  machinemen  and  every- 
body helped  to  tear  down  the  machines  and  bars.  Then  J^  X  36  X  140- 
in.  slick  sheets  were  spread  out  for  30  ft.  back  from  the  face  and  covered 
with  a  little  muck.  These  sheets  were  handled  with  grappling  hooks 
through  holes  in  each  corner.  When  the  machines  were  removed,  an  air 
hose  was  attached  to  a  blow  pipe  and  the  holes  cleaned.  The  shift  boss, 
machinemen  and  foreman  then  did  the  loading.  Spitting  the  fuses  com- 
pleted the  cycle.  There  is  no  relation  whatever  between  the  shift  and  the 
drilling  cycle,  the  machinemen  relieving  each  other  without  stopping 
drilling. 

Beginning  with  the  time  the  last  hole  was  heard  to  explode,  the 
average  time  schedule  for  the  last  five  months'  operations  would  be  about 
as  follows: 

Time  consumed, 
Operations  minutes 

Returning  to  face 4 

Setting  top  bar 6 

Mounting  and  starting  up  two  machines 3 

Shoveling  back  for  bottom  bar 30 

Drilling  20  to  25  holes 210 

Tearing  down  machines 5 

Blowing  out  holes 4 

Loading  holes 6 

Cutting  and  spitting  fuses 

Interval  to  report  of  first  hole 4 

Interval  from  report  of  first  hole  to  report  of  last  hole .  3 


Total 4  hr.   37  min. 

In  drilling  the  round  the  standard  center  cut,  generally  with  six  holes, 
was  used;  these  cut  holes  varied  from  7^  to  8  ft.  The  side  holes  and 
lifters,  which  averaged  5^  ft.,  were  put  in  to  suit  the  ground.  Varia- 
tions in  the  nature  of  the  information  necessitated  a  good  deal  of  variation 
in  the  layout  of  the  holes.  A  good  many  relievers  and  " kickers"  were 
frequently  necessary.  The  usual  round  required  21  to  23  holes,  although 
at  times  29  were  necessary..  For  a  22-hole  round  the  total  footage  was 
about  140;  the  average  rate  of  drilling  dry  holes  was  6  ft.  per  hour,  of 
drilling  wet  holes,  7  to  10  ft.  per  hour. ;  the  average  time  for  a  complete 
round  was  3J^  to  5  hr. ;  the  average  advance  per  round  was  about  4  ft. 


180  DETAILS  OF  PRACTICAL  MINING 

The  muck  from  the  face  was  hand  trammed  at  first;  subsequently  a 
storage-battery  locomotive  was  used,  transporting  material,  men  and 
waste  rock.  This  was  a  4-ton  Jeffrey  machine,  equipped  with  63  Edison, 
A-8,  nickel-steel  cells.  The  Matheson  side-dumping  roller-bearing  cars 
used  had  a  capacity  of  30  cu.  ft.  Drill  steel  and  miscellaneous  material 
were  handled  principally  on  small  flat  cars.  The  30-ft.  capacity  cars 
were  the  largest  that  could  be  used  on  the  slick-sheet  sidings.  They  were 
loaded  heaping  full,  since,  when  loaded,  they  did  not  require  to  be  derailed. 
The  track  gage  was  24  in.,  the  widest  for  which  the  side-dump  cars  could 
be  built  and  allow  the  loaded  car  on  the  track  to  pass  the  empty  on  the 
siding.  At  the  beginning  of  operations,  the  locomotive  hauled  out  12 
cars  in  a  train,  but  as  the  length  of  the  tunnel  increased,  it  became  neces- 
sary eventually  to  handle  trains  of  30  cars.  The  material  was  used  for 
fills  on  the  surface  railroad  between  the  tunnel  portal  and  the  mill  site,  the 
filling  being  dumped  from  temporary  trestles  constructed  for  the  purpose. 
One  motorman  and  one  brakeman  handled  and  dumped  the  trains. 

An  exhaust  ventilating  system  was  used.  The  first  fan  was  placed 
just  outside  the  tunnel,  exhausting  3000  cu.  ft.  of  free  air  per  minute;  at 
3000  ft.  in  a  second  fan  was  installed  in  series  to  handle  the  same  amount 
of  air;  at  intervals  of  about  2550  ft.  additional  fans  were  installed.  A 
15-in.  ventilating  pipe  was  made  up  of  18-gage  galvanized  iron  in  25-ft. 
lengths.  The  lengths  were  provided  with  slip  joints  with  lugs  for  wiring 
them  together;  all  joints  were  wrapped  with  tarred  canvas  to  insure  their 
being  air-tight.  The  ventilating  pipe  was  carried  on  4  X  6-in.  vertical 
posts  spaced  15  ft.  It  was  kept  close  to  the  face  and  protected  by  a  bulk- 
head of  ties.  A  compressed-air  line  was  carried  along  the  bottom  on 
4  X  4-in.  sills,  which  also  supported  the  board  walk;  the  end  of  t-his  pipe 
was  protected  by  the  same  bulkhead.  The  main  line  was  always  thus 
within  a  hose  length  of  the  face.  The  arrangement  is  shown  in  Fig.  140. 

The  rails  were  50  lb.,  laid  on  6  X  8-in.  by  6-ft.  ties.  Six  wires  were 
carried  the  length  of  the  tunnel;  three  of  these  were  used  for  the  single- 
phase,  110-volt  lighting  system,  the  purpose  of  the  third  wire  being  to 
give  equal  voltage  at  all  points  in  the  tunnel.  The  other  three  wires 
constituted  the  three-phase,  440-volt  alternating  circuit  for  the  ventilat- 
ing-fan  motors. 

Drilling  was  started  November,  1912,  but  the  work  was  not  considered 
as  completely  organized  until  December,  1912.  Between  Dec.  1,  1912, 
and  April  1,  1914,  a  period  of  16  months,  the  tunnel  was  advanced  8707  fir. 
with  a  single  heading,  an  average  of  544.2  ft.  per  month.  During  the  last 
six  months,  the  average  monthly  advance  was  596  ft.  The  greatest 
monthly  advance  was  661  ft.  made  in  November,  1913.  At  various  times 
advances  of  24  ft.  per  day  were  made. 

On  account  of  the  peculiar  shift  arrangement,  the  men  were  paid  by 


DRIFTING 


181 


182  DETAILS  OF  PRACTICAL  MINING 

the  hour,  and  in  addition  a  bonus  was  distributed.  The  foreman  distrib- 
uted this  according  to  his  judgment.  His  idea  was  to  give  the  greatest 
reward  and  the  greatest  incentive  to  the  men  chiefly  responsible  for  the 
rate  of  progress.  The  result  was  thoroughly  satisfactory. 

The  following  cost  data  apply  to  the  8707  ft.  driven  between  Dec.  1, 
1912,  and  April  1,  1914,  this  representing  the  distance  driven  under  the 
standard  conditions  described: 

Wages $14.72 

Bonus 4.14 

Explosives 4 . 47 

Lighting 0 . 28 

Tool  replacement 1 . 35 

Lumber  and  miscellaneous  supplies 0 .  ?5 

Store  expense  and  transportation 0 . 38 

Power  and  compressed  air 2 . 53 

Loss  on  boarding  house 1.17 

Depreciation  on  mining  tools 1 . 29 


Total $31 .08 

DRILLING  ROUNDS 

Leyner  Drilling  Rounds  (By  Charles  A.  Hirschberg). — Reciprocating 
drills  are  restricted  in  their  application  to  certain  drilling  rounds,  while 
mounted  hammer  drills,  such  as  the  Leyner,  are  readily  applicable  to  the 
drilling  of  all  kinds  of  drift  rounds.  The  piston  or  reciprocating  machines 
are  unsuitable  for  rounds  of  holes  calling  for  drilling  close  to  the  top  or  side 
walls  and  at  a  slight  pitch;  such  machines  require  ample  head  and  wall 
room  for  operation;  consequently  they  are  slow  in  operation  and  hard  to 
handle. 

Fig.  141,  at  1,  shows  a  round  of  holes,  to  which  the  term  "Leyner 
cut "  has  been  applied,  used  in  a  drift  or  tunnel  where  the  rock  is  extremely 
hard.  It  has  been  used  with  variations  in  the  mines  of  Arizona,  Colorado, 
and  Michigan.  It  involves  a  pyramid  or  center  cut  including  a  great 
many  upper  or  dry  holes.  The  advantages  of  the  Leyner  cut  are:  (1) 
The  holes  are  drilled  with  as  few  changes  of  machines  and  set-ups  as 
possible;  (2)  a  pyramid-shaped  wedge  of  rock  is  first  pulled  from  the  cen- 
ter, after  which  the  rest  of  the  round  breaks  readily.  While  there  is  no 
hard-and-fast  method  of  putting  in  such  a  round  of  holes,  the  principle  is 
the  same  in  all  cases  and  involves  the  many  upper  and  dry  holes  shown  in 
the  illustration. 

Referring  to  the  illustration,  C  designates  the  position  of  the  crank 
of  the  drill  in  each  case.  A  is  a  crossbar  in  the  first  position.  From  the 
top  of  the  bar  the  four  back  holes,  9,  10,  11  and  12,  are  drilled.  The 
machine  is  then  "dumped"  or  tipped  forward  until  the  crank  can  just 


DRIFTING 


183 


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FIG.  141. VARIOUS  LEYNER  DRIFT  ROUNDS. 


184  DETAILS  OF  PRACTICAL  MINING 

turn  and  clear  the  back  or  top  of  the  drift,  is  moved  out  a  little  on  the  bar 
and  the  top  center-cut  holes  1  and  2  are  drilled.  If  the  bar  is  set  up  cor- 
rectly in  a  drift  of  the  size  shown,  the  machine  can  be  dumped  enough  to 
reach  the  center  of  the  drift  heading  with  the  bottom  of  the  hole.  The 
machine  is  then  turned  under  the  bar  and  the  side  holes  7  and  8  and  the 
cut  holes  5  and  6  are  drilled.  The  crossbar  is  next  dropped  to  position  B, 
the  machine  is  set  up  on  top  and  the  side  holes  13  and  14  drilled.  Finally, 
the  machines  are  turned  under  the  bar,  tipped  up  in  front  so  that  the 
crank  just  clears  the  bottom  of  the  drift  and  holes  3  and  4  are  drilled  so 
as  about  to  meet  1  and  2  in  the  center  of  the  heading.  The  four  lifters, 
15,  16,  17  and  18,  are  drilled  last,  except  that,  if  there  is  time  enough, 
relievers  something  like  X  and  Y  may  be  put  in  to  make  sure.  When 
sufficiently  strong  explosive  is  used,  however,  the  round  will  break  with- 
out these  last. 

The  full  round  shown  in  the  illustration  is  designed  for  hard  rock,  but  a 
modified  round  of  this  kind  could  be  used  almost  anywhere.  In  softer 
and  better  breaking  ground,  cut  holes  5  and  6,  relievers  X  and  F,  one  lifter 
and  one  back  hole  can  be  left  out,  but  the  four  cut-holes  1,  2,  3  and  4  are 
nearly  always  used  and  are  pitched  up  or  down,  and  in,  to  meet  about  at 
the  center.  There  are  two  reasons  why  this  round  is  practically  impossible 
with  piston  drills.  First,  they  cannot  drill  it  fast  enough,  particularly 
on  account  of  the  dry  holes;  and  second,  the  size  of  the  piston  drill  is  too 
great  to  permit  operating  it  in  the  positions  necessary  to  give  the  holes  the 
proper  pitch  and  angle.. 

At  2  is  shown  another  pyramid  cut  as  used  in  some  of  the  mines  of 
Mexico  for  driving  small  drifts  in  hard  rock.  This  round  is  drilled  from 
an  arm  mounted  on  a  column,  A  and  C,  A1  and  C1  representing  the  ver- 
tical positions  of  the  arm,  and  A2  the  horizontal  position  of  the  arm  and 
drill  on  both  sides  of  the  column;  the  column  is  placed  midway  between 
the  walls  of  the  drift.  Holes  4  and  5  are  first  drilled  from  the  top  of  the 
arm,  on  the  right-hand  set-up.  The  drill  is  then  swung  under  the  arm 
and  hole  6  put  in.  Next  the  arm  is  swung  to  the  left-hand  side  of  the 
column  and  hole  7  drilled.  The  machine  is  turned  to  the  top  of  the  arm 
and  holes  1,  2  and  3  are  drilled.  The  arm  and  drill  are  then  dropped  to 
C  and  hole  8  drilled;  the  machine  is  swung  under  and  9,  10  and  11  put  in. 
Holes  13  and  14  are  drilled  by  swinging  the  arm  and  drill  to  the  right  of 
the  column  with  the  machine  underneath.  The  machine  is  turned  on 
top  of  the  arm  and  hole  12  drilled,  which  completes  the  round.  For 
extremely  hard  ground  extra  holes  may  be  drilled  with  the  arm  and 
machine  at  B}  but  in  all  moderately  hard  rock  this  has  not  been  found 
necessary. 

A  round  of  holes  employed  in  the  mines  of  South  Africa,  in  a  drift  9  ft. 
wide  by  7  ft.  high,  is  shown  at  3.  It  usually  comprises  12  holes.  Hole 


DRIFTING  185 

13  is  sometimes  drilled  when  the  rock  is  not  breaking  properly,  while  both 
13  and  14  are  used  when  extremely  hard  rock  is  encountered.  The  dis- 
tance between  holes  1,  2,  3  and  4  in  the  vertical  line  is  approximately  2  ft., 
likewise  the  distance  between  holes  5,  6,  7  and  8.  Holes  9,  10,  11  and  12, 
or,  in  other  words,  the  cut  holes,  are  put  in  approximately  4  ft.  apart  at 
the  face  of  the  rock,  but  holes  9  and  10  slant  downward  and  inward  and 
meet  holes  11  and  12,  which  slant  upward  and  inward.  The  distance 
between  the  junction  of  holes  9  and  11,  and  10  and  12,  at  the  bottom,  is 
approximately  18  in.  Hole  13,  when  used,  is  put  in  1%  ft.  below  the  top 
of  the  drift  and  slanting  downward  until  it  comes  to  about  a  central  point 
18  in.  from  the  junction  of  holes  9  and  11  and  from  that  of  10  and  12. 
Hole  14,  when  used,  is  put  in  at  the  face,  about  2  ft.  6  in.  from  the  center 
of  the  cut,  and  slants  in  as  shown  to  a  distance  of  about  18  in.  from  the 
junction  of  holes  10  and  12.  Usually,  however,  holes  13  and  14  are  not 
used.  The  round  of  12  holes  generally  breaks  between  5^£  and  6  ft. 
of  ground.  The  machine  is  mounted  on  a  column  and  arm. 

A  round  used  in  the  Cripple  Creek  district  of  Colorado  is  shown  at  4. 
It  consists  of  17  holes  and  is  used  only  in  drifts  8  ft.  high  by  6  ft.  wide  or 
larger,  where  the  rock  is  an  exceedingly  hard  phonolite.  It  will  be  noted 
that  with  the  exception  of  the  back  holes  1,  2  and  3,  all  the  holes  point 
downward.  This  round  will  break  between  5  and  6  ft.  of  ground.  The 
same  round  is  shown  at  5,  modified  for  a  smaller  drift,  one  7  ft.  high  and 
5  ft.  wide.  It  consists  of  but  1 1  holes  and  is  used  for  drilling  in  brecciated 
formation  and  in  vein  matter.  The  ordinary  double-screw  column  with 
one  set-up  is  used  for  both  rounds.  Of  course,  the  arm  is  shifted  from 
side  to  side  and  lowered  as  occasion  requires,  the  holes  being  drilled  from 
both  above  and  below  the  arm.  These  rounds  are  varied  slightly  with 
the  nature  of  the  ground;  fewer  holes  are  sometimes  drilled,  but  never 
more. 

A  round  used  several  years  ago  in  driving  the  Lucania  tunnel  at  Idaho 
Springs,  Colo.,  is  illustrated  at  6.  This  tunnel  is  9  ft.  6  in.  high  by  8  ft. 
wide,  and  the  advance  averaged  between  7  ft.  6  in.  and  8  ft.  per  round. 
The  set-up  involved  the  use  of  two  columns,  one  carrying  two  arms  and 
the  other  one  arm,  making  a  total  of  three  machines.  Short  cut-holes  1, 
2  and  3  were  drilled  6  ft.  deep;  long  cut-holes  4,  5,  6,  7,  8  and  9,  9  ft.  6  in. 
deep;  relievers  10,  11,  12  and  13,  8  ft.  deep;  back  holes  14,  15  and  16,  8 
ft.  deep;  side  holes  17,  18,  19,  20,  21  and  22,  8  ft.  deep;  lifters  23,  24  and 
25,  8  ft.  deep.  Holes  6,  2,  3,  9,  11,  13,  23,  24  and  25  were  drilled  by  the 
bottom  machine;  the  rest  were  drilled  by  the  two  top  machines.  The 
round  was  shot  in  the  order  numbered,  the  two  cuts  being  loaded  and 
fired  first.  The  remainder  of  the  round  was  then  loaded  and  fired. 

A  round  employed  in  the  Michigan  copper  country  for  what  is  known 
as  a  drift  stope  is  exhibited  at  7,  the  width  of  the  working  varying  according 


186 


DETAILS  OF  PRACTICAL  MINING 


to  the  width  of  the  lode;  the  object  is  to  take  out  all  of  the  rock  between 
the  foot  and  hanging  walls,  the  holes  being  pointed  in  some  cases  toward 
the  foot  and  in  others  toward  the  hanging.  The  round  as  illustrated 
would  do  for  an  8  X  14-ft.  drift.  The  set-up  consists  of  a  double-screw 
column  with  arm. 

At  8  is  shown  the  method  in  use  at  the  Quincy  mine  for  small  drifts; 
it  works  satisfactorily  in  this  particular  case  owing  to  the  fact  that  the 
driving  is  done  entirely '  through  trap,  there  being  no  copper  to  contend 
with.  This  round  is  not  good,  however,  in  ground  that  is  heavily  charged 
with  copper,  since  great  difficulty  would  be  encountered  in  getting  the 
cuttings  out  of  the  holes.  In  such  cases  the  direction  of  the  holes  should 


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FIG.    142. SUCCESSFUL  ROOSEVELT-TUNNEL  ROUND. 

be  reversed  so  as  to  point  upward.  The  round  is  shown  for  a  6  X  7-ft. 
drift  and  is  drilled  from  column  and  arm.  The  holes  are  drilled  to  the 
following  depths:  1,  2  and  3,  2  ft.  6  in.  deep;  3,  4,  14  and  15,  3  ft.  6  in. 
deep;  19,  20  and  21,  4  ft.  deep;  5,  6  and  16,  4  ft.  6  in.  deep;  9,  10,  11,  12 
and  18,  5  ft.  8  in.  deep;  7,  8  and  17,  6  ft.  deep. 

At  9  is  illustrated  a  round  of  holes  for  an  8  X  12-ft.  drift  as  used  in  the 
Dober  mine  near  Iron  River.  The  ground  was  a  gray  slate.  The  holes 
were  drilled  from  a  column  and  arm  and  required  two  set-ups,  owing  to  the 
wideness  of  the  drift.  All  holes  were  drilled  to  a  depth  of  5  ft.  with  the 
exception  of  those  numbered  5,  6,  15  and  16,  which  were  drilled  5  ft.  6  in. 
deep. 

A  round  employed  in  medium-hard  iron  ore  at  the  Gary  mine,  Hurley, 


DRIFTING 


187 


Wis.,  is  shown  at  10.  The  size  of  the  drift  is  8  X  8  ft.  All  holes  with 
the  exception  of  18, 19  and  20  look  up  a  little  above  the  horizontal.  Holes 
1,  2,  4,  5,  9,  10,  12,  13  and  17  are  drilled  5  ft.  deep;  18, 19  and  20,  5  ft.  6  in. 
deep;  3,  6,  7,  11,  14  and  15,  5  ft.  8  in.  deep;  8  and  16,  6  ft.  6  in.  deep. 
This  cut  breaks  well  and  lengthens  the  drift  4J^  ft.  with  each  round.  The 
round  is  drilled  with  column  and  arm  set-up. 

After  the  trial  of  several  systems  of  placing  the  drill  holes  for  the 
Roosevelt  tunnel,  that  shown  in  Fig.  142  finally  proved  to  be  best  adapted 
to  the  tough  nature  of  the  jointless  rock.  Water-Leyner  drills  were 
employed.  In  attacking  the  ordinary  rock,  all  holes  were  drilled  8  ft. 
except  the  cuts  and  relief  cuts,  Nos.  1  to  8,  inclusive,  which  were  drilled 
to  a  10-ft.  depth.  In  tougher  ground,  these  depths  were  each  cut  down  2 


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FIG.    143. LARAMIE-POUDRE  ROUND. 

ft.,  and  in  addition  to  the  22  holes  used  on  the  ordinary  rock  and  num- 
bered in  the  illustration,  the  six  extra  holes  X  were  put  in.  At  first,  even 
with  the  use  of  from  300  to  350  Ib.  of  60  per  cent,  dynamite,  great  diffi- 
culty was  experienced  in  properly  blasting  the  eight  cut-holes,  sometimes 
several  loadings  being  necessary  to  blow  out  the  cut.  Finally,  however, 
after  putting  in  the  two  extra  cuts  shown,  even  the  toughest  ground 
yielded.  The  system  of  placing  the  holes  was  evolved  with  a  view  not 
only  to  blasting  the  rock  to  the  best  advantage,  but  also  to  allow  the 
greatest  economy  of  time  in  drilling.  These  ends  proved  to  be  best 
effected  by  mounting  the  two  Leyner  drills  on  a  single,  horizontal  cross- 
bar, instead  of  on  the  more  usual  two  independent  vertical  columns.  In 
this  way  even  the  maximum  number  of  28  holes  required  but  two  set-ups 


188  DETAILS  OF  PRACTICAL  MINING 

of  the  bar.  The  grade  line  was  carried  about  18  in.  below  the  top  of  the 
bore  and  about  8  to  12  in.  below  this  was  placed  the  bar.  From  this,  the 
center  and  corner  back-holes  were  drilled,  and  then  by  revolving  the  drill 
around  and  beneath  the  supporting  bar,  all  of  the  remaining  holes  except 
center  lifters  and  bottom  corners  were  put  in.  From  the  second  position 
of  the  bar,  usually  about  18  to  24  in.  above  the  floor,  the  last  four  holes 
were  put  in.  In  tough  ground  an  extra  center-cut  hole  X  was  also  put  in 
from  this  set-up. 

The  Laramie-Poudre  tunnel  at  the  beginning  of  the  year  1911  held  the 
best  two  American  tunnel-driving  records:  609  ft.  in  January,  1911,  and 
653  ft.  in  March.  Fig.  143  shows  the  layout  of  the  holes  in  regular  work. 
The  holes  were  drilled  and  shot  in  the  succession  numbered  in  the  cut, 
requiring  two  set-ups  of  the  tunnel  bar,  no  column  being  used.  The  upper 
set-up  was  drilled  on  top  of  the  muck  pile,  and  in  the  meantime  the  muck 
was  cleared  away,  when  the  bar  was  lowered  and  the  lifters  put  in.  Holes 
were  started  2%  in.  in  diameter  and  bottomed  at  1%  in.  Two  water 
Leyner  machines  were  used,  drilling  10-ft.  and  12-ft.  holes.  In  case  of 
extremely  hard  rock  a  third  machine  was  mounted,  each  machine  drilling 
holes  as  follows:  Those  lettered  LT  were  drilled  by  the  left-hand  machine 
on  the  top  set-up,  those  marked  CT  by  the  center  machine  on  the  top 
set-up,  and  those  marked  RT  by  the  right-hand  machine  on  the  top  set- 
up. The  bar  was  then  lowered  and  each  machine  put  in  a  lifter,  lettered 
LB,  CB  and  RB.  The  blasting  charge  for  a  round  generally  consisted 
of  about  100  sticks  of  100  per  cent,  gelatin,  150  sticks  of  60  per  cent,  and 
250  sticks  of  50  per  cent. 

Drift  Round  in  Flat  Sediments. — In  Fig.  144  is  shown  the  side-cut 
drift  round  used  in  southeastern  Missouri  for  drifts  in  the  flat-dipping 
dolomite  that  forms  the  country  rock.  The  drifts  are  about  6^  ft.  high 
and  8  ft.  wide.  Other  types  of  rounds  have  been  tried.  In  one  of  the 
mines  where  Leyner  drills  are  used,  the  Leyner  center,  pyramidal  cut  has 
been  tried,  but  it  did  not  prove  so  satisfactory  as  the  side  cut.  The 
Western  cut,  in  which  the  holes  are  drawn  from  the  bottom  with  lifters  to 
take  up  the  bottom  bench  lift  under  the  cut,  has  also  been  tried,  but  the 
side-cut  has  held  its  own. 

Only  at  the  mines  of  the  Desloge  Consolidated  is  there  used  a 
different  cut.  There,  when  drifting  in  ore,  a  center  V-shaped  cut  is  used 
in  the  drift,  and  a  drift  11  ft.  wide  and  6J^  ft.  high  is  driven.  This,  it  is 
stated,  can  be  advanced  as  fast  as  the  smaller  drift.  Two  one-man 
machines  drill  18  holes  to  the  round  making  a  total  drilling  of  about  100 
ft.  A  round  will  square  up  about  5  ft.,  while  the  average  speed  is  90  to 
100  ft.  per  25-day  month.  About  50  Ib.  of  dynamite  breaks  the  25  to 
30  tons  of  rock  coming  from  the  round.  The  only  extra  expense  is  in 
handling  the  rock  and  when  the  work  is  in  ore  this  is  broken  much  more 


DRIFTING 


189 


cheaply  owing  to  the  much  smaller  amount  of  dynamite  used  per  ton 
broken. 

The  reason  the  side-cut  proves  so  satisfactory  in  this  sedimentary  for- 
mation is  that  the  holes,  owing  to  the  flat  dip  of  the  limestone,  are  always 
kept  in  the  same  bed.  Consequently,  they  are  easier  to  drill  and  break 
better  from  being  in  rock  of  the  same  character  for  their  entire  depth. 
Where  drilled  downward  there  is  frequently  a  tendency  for  the  holes  to 
" bull-ring,"  breaking  out  in  the  weaker  beds  and  leaving  the  more 
resisting  beds  standing.  This  causes  the  holes  that  follow  to  break 
poorly,  and  the  entire  round  is  often  held  up. 

Two  one-man  piston  drills  are  usually  used  in  a  drift,  one  mounted 


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FIG.    144. SOUTHEASTERN  MISSOURI  SIDE  CUT  FOR  DRIFTS. 

on  each  side  of  a  vertical  column.  With  two  drills  a  round  can  be  drilled 
and  blasted  in  one  shift.  In  drifting  the  drilling  is  done  only  on  day  shift, 
and  the  machine  men  always  have  a  clean  face  to  start  with.  A  one-man 
piston  machine  will  drill  about  40  ft.  of  hole  in  average  ground,  taking  out 
the  time  required  in  setting  up  and  loading  and  blasting.  A  Leyner  drill 
has  often  been  known  to  put  in  a  drift  round  in  a  shift  with  one  man  run- 
ning it,  in  the  mines  where  that  type  of  drill  is  used. 

With  this  side  cut,  the  round  is  alternated  from  one  side  to  the  other. 
A  round  will  square  up  from  4  to  4^  ft.  per  shift,  and  the  average  speed 
of  drifting  in  the  district  is  about  90  ft.  per  month  of  26  days.  Generally 
from  11  to  14  holes  will  break  a  round  as  shown  in  the  accompanying  dia- 


190 


DETAILS  OF  PRACTICAL  MINING 


gram.  About  20  Ib.  of  dynamite  per  foot  is  used  in  such  a  drift  and  from 
12  to  18  tons. broken  by  a  round.  The  cost  is  about  $10  to  $11  per  foot, 
of  which  about  25  per  cent,  is  for  labor,  this  cost  covering  the  direct 
charges  such  as  breaking,  shoveling,  tramming,  drill  upkeep,  air  and 
explosives. 

Rapid  Drifting  by  St.  Joseph  Lead  Co. — The  St.  Joseph  Lead  Co. 
connected  its  No.  1  and  No.  7  mines  at  Bonne  Terre,  Mo.,  with  a  drift 
7  ft.  high  by  12  ft.  wide  in  hard  unstratified  limestone.  A  record  of  455  ft. 
was  made  in  25  working  days  of  three  shifts  each,  or  75  eight-hour  shifts. 
The  force  consisted  of  three  machine  men,  three  chuck  tenders,  two 
muckers  and  one  mule  driver  for  each  shift.  Three  Sullivan  2%-in. 
piston  drills  were  used;  the  air  was  supplied  under  90-lb.  pressure.  The 


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FIG.    145. FIFTEEN-HOLE  EOUND  FOB  WIDE  DRIFT. 

drilling  was  done  from  a  crossbar  to  which  were  attached  three  arms 
similar  to  those  used  on  columns.  This  enabled  the  miners  to  work  the 
machines  one  above  the  other  when  necessary,  and  if  one  side  of  the  drift 
was  harder  than  the  other,  one  of  the  machines  could  be  moved  over  to 
the  hard  side  so  as  to  drill  *n  any  position  desired,  without  interfering  with 
either  of  the  others. 

To  pull  a  6-ft.  cut  15  holes  were  necessary,  placed  as  shown  in  Fig.  145. 
The  cut  holes  were  drilled  to  meet  at  the  points.  A  vertical  row  of  three 
relief  holes  widened  out  the  cut  and  the  six  side  holes  finished  squaring 
the  face.  When  the  ground  was  harder  than  usual,  eight,  instead  of  six 
cut  holes  were  used.  Each  of  the  cut  holes,  1,  2,  3,  4,  5  and  6  was  charged 
with  six  to  eight  1M  X  8-in.  cartridges  of  For  cite  60  per  cent,  gelatin 
dynamite.  Each  of  the  remaining  holes  received  three,  four  or  five 


DRIFTING 


191 


cartridges  of  the  same  explosive,  according  to  the  character  of  the  rock 
encountered,  making  80  to  90  cartridges,  62  to  72  lb.,  for  the  entire  round. 
This  gives  an  average  of  11.2  lb.  of  explosive  per  foot,  or  1.44  lb.  per  ton  of 
rock. 

The  blasting  was  all  done  by  electricity.     Victor  electric  fuses  were 


FIG.    146. COMPARISON  OF  PISTON-MACHINE  AND  STOPER  DRIFT  ROUNDS. 

used.  The  No.  5  were  discarded  for  No.  8  on  account  of  the  better  results 
in  the  work  done  by  the  explosive  and  in  the  character  of  the  fumes  after 
blasting.  The  blasting  machines  used  were  the  Reliable  No.  3  and  No.  4. 
The  lead  wire  was  500  ft.  of  Duplex  No.  14  B.  &  S.  gage.  The  blasting 
was  done  from  small  chambers  cut  in  the  side  of  the  drift.  The  drilling, 


192  DETAILS  OF  PRACTICAL  MINING 

including  setting  up  and  tearing  down,  took  six  hours.  The  blasting  oc- 
cupied about  one  and  one-half  hours. 

Drifting  with  a  Stoper  (By  G.  E.  Wolcott). — The  stoper  has,  through 
the  requirements  of  the  leaser  and  small  operator,  been  adapted  to  drifting. 
In  the  case  of  the  leaser,  low  equipment  expense  is  imperative.  It  is  this 
fact  rather  than  any  advantage  of  the  machine  itself  that  is  responsible 
for  its  use  for  drifting. 

In  the  Cripple  Creek  district  the  drifts  are  usually  from  3^  X  6J£  ft. 
to  5  X  8  ft.,  and  the  arrangement  of  holes  for  a  piston  machine  in  average 
ground  is  generally  as  shown  in  Fig.  146.  When  the  stoping  machine  is 
used  for  drifting,  holes  are  placed  differently.  Since  flat-  and  down-holes 
are  drilled  with  difficulty  by  this  machine,  as  many  holes  as  possible  are 
inclined  upward,  and  as  a  rule  only  the  two  lifters  are  drilled  looking  down. 
In  2  is  shown  the  general  arrangement  of  holes.  A  set-up  is  made  by 
using  a  plank  leaning  against  a  sprag  as  shown.  The  spud  of  the  machine 
is  placed  against  the  bottom  of  the  plank  for  drilling  all  holes  except  the 
lifters ;  for  the  latter  it  is  raised  a  foot  or  more,  as  desired.  The  face  of  the 
drift  is  not  ordinarily  kept  vertical,  because  the  holes  are  more  readily 
drilled  with  an  inclined  breast  as  shown.  The  holes  do  not,  however,  have 
a  good  show  to  break  to  start  the  round,  and  in  order  to  keep  the  back  to 
the  required  height  it  is  necessary  to  drill  the  holes  deeper  than  they  will 
break.  A  better  arrangement,  and  one  requiring  fewer  holes,  is  shown  in 
3,  in  which  the  cut  holes  are  bottomed  as  near  the  center  of  the  breast  as 
possible,  where  they  have  the  best  chance  to  break.  With  the  stoper  it  is 
impossible  to  obtain  so  good  a  cut  as  with  a  piston  machine,  and  in  hard- 
breaking  rock  this  must  be  offset  by  an  increased  number  of  holes. 

A  drawback  to  the  use  of  the  stoper  for  drifting  is  the  fact  that  the 
muck  must  be  thrown  back  farther  from  the  breast  to  make  room  for  the 
machine.  The  ordinary  stoper  requires  not  less  than  6  ft.  between  the 
spud  and  the  breast.  If  the  stoping  bar  is  shortened,  too  many  changes 
of  steel  are  necessary. 

Recording  Mine  Timbering  (By  John  T.  Fuller). — The  method  of 
posting  mine  timbering  here  described  refers  especially  to  "  gang  ways" 
or  drifts,  but  can  easily  be  extended  to  embrace  all  timbering,  such  as 
that  of  shafts,  etc.  It  is  difficult  to  keep  track  of  the  timbering  in  a  large 
mine.  The  timber  in  any  particular  tunnel  is  put  in,  as  a  rule,  at  different 
times  as  the  work  progresses;  retimbering  is  perhaps  of  frequent  occur- 
rence and  the  age  of  the  timbering  or  of  any  particular  set  of  timber,  the 
cause  of  failure  and  many  other  items  of  information  that  are  of  value  to 
the  mine  manager  soon  become  hopelessly  confused  and  lost.  The  method 
of  computing  the  cost  of  timbering  at  many  mines  is  simply  to  charge 
against  this  item  the  timber  sent  underground  and  the  labor  involved  in 
preparing  and  setting  the  same.  Where  timbering  and  retimbering  are 


DRIFTING  193 

done  by  contract  and  payment  made  once  a  month  or  once  a  fortnight  it 
becomes  absolutely  imperative  in  fairness  both  to  the  company  and  to  the 
contractor  to  adopt  some  system  of  recording  or  posting  the  timber  sets. 
Unless  some  good  system  is  in  effect  both  the  contractor  and  the  head 
timberman,  or  other  company  men  in  authority,  are  likely  to  become 
confused  and  uncertain  as  to  exactly  what  timbers  have  been  set  during 
the  period  in  question.  Especially  is  this  true  in  the  case  of  retimbering, 
which  frequently  means  simply  resetting  timbers  at  irregular  intervals. 

In  one  case  it  was  attempted  to  keep  track  of  the  timbering  by  having  a 
special  set  of  tracings  made  of  each  level  in  the  mine.  When  the  engi- 
neers posted  the  development  work  at  the  end  of  each  period  they  also 
posted  the  timbering  with  the  aid  of  the  head  timberman.  Each  set  was 
then  plotted  on  the  tracings  in  its  proper  place.  So  far  as  keeping  track 


FIG.    147. — METHOD    OF    MARKING    DRIFT    TIMBERS 

of  the  new  timbering  was  concerned  this  plan  was  a  success,  but  in  trying 
to  keep  the  retimbering  posted  in  this  way,  the  tracings  soon  became 
hopelessly  confusing.  This  fact,  together  with  the  amount  of  extra  work 
thrown  upon  the  already  overworked  engineering  department,  led  to  the 
abandonment  of  this  scheme  as  impracticable. 

The  problem  was  finally  solved  as  follows:  A  set  of  11  steel  figures, 
including  a  spacer,  was  ordered.  Every  stick  of  timber  in  the  mine  after 
being  set  in  position  was  blazed  with  an  ordinary  carpenter's  hatchet  and 
the  date  of  setting  punched  thereon  with  the  steel  figures,  and  then  painted 
over  with  one  coat  of  a  wood  preservative  paint  as  indicated  in  the 
accompanying  drawing.  In  the  drawing,  Fig.  147,  the  blaze  mark  and  the 
date  are  exaggerated  for  the  sake  of  clearness. 

The  head  timberman  on  his  final  round  just  before  the  end  of  the  shift, 
took  with  him,  in  a  canvas  bag  slung  over  his  shoulder,  the  steel  figures 

13 


194 


DETAILS  OF  PRACTICAL  MINING 


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DRIFTING  195 

required  to  mark  the  date  of  that  day,  a  small  hatchet,  about  two  pints  of 
paint  in  a  specially  stoppered  can,  a  brush,  pads  of  the  "Retimber  Sheet" 
form,  shown  in  Fig.  148,  and  of  anotRer  form  called  the  "Timber  Sheet" 
in  which  the  columns  marked  " Date  of  old  timber  put  in"  and  "Life"  are 
omitted  and  the  heading  of  the  last  column  "  Cause  of  Failure"  is  changed 
to  "  Remarks."  He  blazed  and  marked  each  timber  as  shown  and  entered 
the  required  data  on  the  proper  form,  leaving  black  columns  which  are 
headed  "Cost  of  Timber,"  "Labor  Cost  Erection,"  "Total  Cost"  and 
"Life."  Before  going  to  the  next  level  he  would  leave  the  filled-out  forms 
at  the  tool-house,  where  at  the  end  of  each  shift  the  timekeeper  found  and 
collected  them.  The  timekeeper  filled  out  the  column  marked  "Labor 
Cost  Erection"  and  checked  the  labor  items.  On  reaching  the  surface 
the  timekeeper  turned  the  forms  over  to  the  storekeeper,  who  filled  out 
the  "Cost  of  Timber"  column  and  returned  the  forms  to  the  timekeeping 
department  where  the  remaining  columns  were  filled  in,  the  whole  sheet 
checked  over  and  delivered  to  the  mine  manager  before  the  miners  and 
other  workmen  in  the  mine  coming  off  shift  had  changed  their  clothes  and 
left  the  mine.  It  was  thus  possible  for  the  manager  to  check  up  any 
questionable  report  with  the  head  timberman  and  the  men  who  had  per- 
formed the  work  before  any  appreciable  time  had  elapsed  after  its 
completion.  The  sheets  were  kept  on  file  by  levels.  The  various  items 
as  shown  by  the  sheets  were  posted  and  totaled  daily  by  the  bookkeeper  on 
the  large  mine-cost  sheets,  so  that  the  end  of  a  period  entailed  no  extra 
work  to  find  the  amount  due  the  contractors  or  the  cost  of  the  mine 
timbering. 

The  date  mark  placed  on  the  timbers  in  the  way  described  will  remain 
clear  and  legible  as  long  as  the  timber  lasts.  Old  timbers  reset  were 
marked  a  second  time,  leaving  the  original  marks  intact  so  that  when  a 
set  of  timber  was  finally  removed  the  individual  pieces  forming  the  set 
practically  told  their  own  history  and  age.  Where  the  timbering  is  done 
by  contract  the  columns  headed  "Labor  Cost  of  Erection"  are  designated 
as  "Cost  of  Contract"  with  subheads;  "Sets,"  "Feet,"  "Rate"  and 
"Cost." 

Mesabi  Underground  Turn  Timbering. — In  underground  mining  on 
the  Mesabi  there  are  nearly  as  many  different  styles  of  timbering  for 
drift  and  crosscut  turnouts  as  there  are  separate  operating  companies. 

On  sublevels,  which  are  nearly  always  temporary,  turnouts  and  curves 
are  put  in  by  the  foreman  without  help  from  the  engineering  department. 
A  simple  turnout  commonly  used  in  such  cases  is  shown  at  1,  Fig.  149. 
Here  three  drift-set  posts  are  taken  out  and  replaced  by  a  set  called  the 
open  set.  The  only  drawback  in  this  method  is  the  loss  of  headroom. 

For  main  levels,  the  chief  considerations  are  permanency  and  ease  in 
tramming.  A  square  turn,  such  as  is  used  on  the  subs,  requires  so  long  a 


196 


DETAILS  OF  PRACTICAL  MINING 


cap  to  enable  motors  or  mules  to  pass  that  it  becomes  weak  and  fre- 
quently causes  a  great  deal  of  trouble  as  the  ground  takes  weight.  It 
has,  therefore,  become  generally  customary  to  put  in  a  carefully  designed 
curve  of  25-  to  40-ft.  radius.  The  method  of  timbering  and  laying  out  the 
curve  then  depends  on  the  captain  or  the  operating  company. 

At  2,  3  and  4  are  shown  standard  main-level  curves  used  by  one  of  the 
large  operating  companies.  The  lines  AB  are  established  by  the  engi- 
neer by  putting  two  nails  in  the  caps.  Then  the  foreman  by  use  of  the 


Cap  lengths  6~4  'between Joggks,excepk.w/iert 
shoirn  otherwise 

•O'TURN-OUT-6-4"-  6-4*-   25' RADIUS 

8 

FIG.    149. — VARIOUS  METHODS  OF  TIMBERING  TRACK  TURNS  ON  MESABI  HAULAGE  LEVELS 

AND  SUBLEVELS. 

blueprint  is  able  to  place  accurately  each  set.  At  5,  6  and  7  are  shown 
curves  that  make  use  of  50-lb.  rails  instead  of  long  timber  caps.  These 
curves  have  the  advantages  of  requiring  less  supervision  and  engineering, 
of  being  stronger,  and  of  not  requiring  so  high  an  excavation  to  secure 
equal  headroom.  At  8  is  shown  a  curve  frequently  found  in  the  mines  of 
one  of  the  larger  companies.  Although  a  good-looking  curve  for  firm 
ground,  it  has  the  disadvantage  of  the  long  cap  C,  which  is  liable  to  break 
before  the  drift  is  ready  to  be  abandoned. 


DRIFTING 


197 


Building  Drywalls,  Sudbury  District  (By  Albert  E.  Hall). — In  the 
Sudbury  nickel  district,  although  a  new  method  is  to  replace  the  drywalls, 
it  is  still  customary  at  present  to  drive  a  small  stope  and  follow  up  with 
two  drywalls  over  which  lagging  is  placed  to  form  a  drift.  The  machines 
are  then  started  breaking  ground  over  the  walls.  Care  is  always  taken 
to  load  the  walls  evenly,  so  that  there  will  be  no  tendency  toward  move- 
ment as  the  result  of  unequal  loading.  Chutes  are  built  in  every  30  ft., 
and  the  even  loading  is  especially  important  at  these  points,  as  slight 
differences  in  weight  will  cause  the  chutes  to  move.  The  stopes  are 
carried  up  on  the  shrinkage  system.  It  is  important  that  the  walls  be 
well  built;  any  defects  may  cause  serious  trouble,  expense  and  delay. 

The  walls  are  built  so  as  to  give  between  track  and  lagging  a  clearance 
convenient  for  walking.  They  are  6  to  7  ft.  high  and  4J/£  ft.  thick.  A 


Section  through  Drift 
FIG.    150. DRYWALL  AND  TIMBER  FOR  DRIFT. 


course  of  timber  is  placed  every  2  ft.,  and  the  timbers  in  each  course  are 
about  2  ft.  apart.  The  timbers  extend  through  the  wall  and  serve  as  a 
bond  to  hold  the  wall  together.  As  a  further  bond,  numerous  headers  are 
put  in.  The  walls  are  built  on  contract  at  12  cts.  per  square  foot  of 
wall  face.  The  company  has  to  furnish  the  contractors  with  stone  and 
timber,  two  trammers  usually  being  assigned  to  the  masons  in  the  event 
that  no  stone  is  convenient.  The  walls  on  the  old  levels  are  pulled  down 
so  that  the  timber  can  be  used  over  on  the  lower  levels.  On  top  of  the 
walls  are  placed  two  rows  of  2-in.  planking  spiked  to  the  top  course  of 
timber  in  the  wall,  one  behind  the  other,  so  as  to  give  a  large  bearing 
surface  for  the  lagging.  Between  the  two  rows  of  planks  about  6  in.  is  left 
and  is  filled  in  with  fine  stuff.  The  method  of  construction  is  shown  in 
Fig.  150.  Care  must  be  taken  that  only  flat  stones  are  put  in  the  wall, 


198  DETAILS  OF  PRACTICAL  MINING 

since  any  that  are  not  flat  cause  either  themselves  or  the  adjoining  stones 
to  be  squeezed  out  when  the  wall  is  loaded.  Strictly  speaking,  drywalls 
are  not  advantageous  where  sufficient  rock  is  not  obtainable  to  do  the 
building.  This  condition  exists  in  the  Sudbury  district,  i.e.,  not  enough 
rock  is  broken  with  the  ore  or  in  development  drifting.  For  this  reason 
some  ore  must  be  used,  and  since  the  ore  has  not  sufficient  crushing 
strength,  some  of  the  walls  have  failed  where  a  piece  of  ore  in  the  face  was 
crushed. 

At  points  opposite  chutes  a  high  wall  is  built,  consisting  of  a  square 
timbered  crib  rilled  in  with  rock  between  the  timbers.  Where  a  drift 
branches,  the  point  is  also  made  of  cribbing,  either  square  or  round,  and  is 
filled  in  with  stone.  A  wall  is  built  around  behind  the  chutes  and  in  some 
cases  mills  are  built  above  them.  These  are  made  round.  The  timber  in 
these  is  laid  in  courses  2  ft.  apart,  as  in  the  walls,  but  the  individual  tim- 
bers are  placed  touching  each  other.  Manways  are  placed  at  suitable 
points  and  are  built  5  ft.  square.  The  timber  in  these  is  placed  in  a  man- 
ner similar  to  that  used  in  building  up  a  mill. 


VI 
STOPING 

Methods — Timbering  and  Substitutes — Filling — Various  Devices 

METHODS 

Stoping  at  the  North  Star  Mine  (By  L.  0.  Kellogg).— At  the  North 
Star  Mine  in  Grass  Valley,  California,  the  ore  occurs  as  a  series  of  shoots  in 
a  flat  quartz  vein.  The  average  dip  is  about  23°,  the  width  about  2  ft., 
but  a  greater  thickness  is  broken  to  get  working  room.  The  main 
inclined  raise,  through  which  material  is  lowered  to  the  vertical  hoisting 
shaft,  has  loading  stations  at  three  levels,  spaced  something  over  300  ft. 
on  the  incline.  To  these  bins  the  ore  is  trammed  from  both  sides  of  the 
raise  by  mule  or  by  hand,  according  to  the  length  of  the  haul  and  the  ton- 
nage handled.  The  ore  from  the  block  above  is  got  to  each  level  by 
means  of  gravity  planes.  These  are  locally  and  aptly  called  "  go-devils." 
They  are  peculiar  in  the  fact  that  the  same  cars  that  are  used  for  tramming 
in  the  stopes  are  lowered  in  balance  on  the  plane  by  means  of  a  light, 
portable  and  easily  controlled  triple-sheave  head-block.  A  typical 
stope  in  process  of  working  by  the  go-devil  method  is  diagrammatically 
illustrated  in  Figs.  151  and  152.  These  exhibit,  by  plans  in  the  plane  of 
the  vein,  four  successive  stages  in  the  working  of  a  stope,  the  earliest  at 
the  top  of  Fig.  151,  the  latest  in  Fig.  152. 

The  inclined  raises  which  are  put  up  at  intervals  for  development  may 
or  may  not  be  in  ore.  A  stope  may  be  started  between  two  raises,  ex- 
tended to  each,  and  may  use  a  go-devil  in  each  raise,  it  may  be  started  on 
both  sides  of  a  raise  and  may  use  a  single  go-devil  in  the  center,  or  it  may 
be  started  in  unexplored  ground  and  an  entirely  new  go-devil  installed 
near  the  middle.  In  describing  the  development  of  a  typical  stope,  we 
may  consider  one  started  on  two  sides  of  a  raise,  which  is  itself  in  ore. 
Such  a  raise  will  have  employed  a  go-devil,  and  the  chute  at  its  bottom 
and  the  tracks  will  have  been  left  in  place. 

The  first  operations  consist  in  drilling  holes  along  the  side  of  the  drift. 
Usually  two  stoping  points  are  selected,  one  on  each  side  of  the  raise,  and 
each  stope  carried  toward  the  raise  in  one  direction  and  to  the  limits  of 
the  oreshoot  in  the  other.  The  first  ore  is  shot  down  on  plats,  usually 
covered  with  steel  sheets,  laid  over  the  level  tracks.  The  stope  soon 
assumes  the  shape  shown  at  the  top  of  Fig.  151. 

199 


200 


DETAILS  OF  PRACTICAL  MINING 


STOPING 


201 


The  foot-wall  of  the  vein  has  usually  been  carried  pretty  well  up  on  the 
side  in  drifting,  so  that  after  two  or  three  cuts  have  been  shot  out,  a 
shoveling  plat  can  be  erected,  the  height  of  a  car  or  higher.  Such  a  plat 
is  illustrated  at  the  top  of  Fig.  153,  consisting  in  its  simplest  form  of  2-in. 
planks,  covered  with  steel,  set  at  right  angles  to  the  track  on  a  round 
timber  supported  by  two  stulls.  In  the  same  way,  small  chutes  or  lips 
can  be  put  in  to  deliver  directly  to  the  cars  without  shoveling  if  the  vein 
is  steep  enough. 

In  this  manner  the  stope  is  carried  up  until  its  face  is  somewhat  above 
the  top  of  the  raise  chute.  About  30  ft.  on  the  dip  may  have  been  thus 
mined.  It  is  squared  up  and  the  pillars  next  the  chute  are  removed. 
Then  a  row  of  stulls  is  placed  within  about  5  ft.  of  the  stope  face  and 
horizontal  poles,  with  a  minimum  diameter  of  6  in.,  are  set  against  these 
so  as  to  keep  the  broken  rock  on  the  intermediate  level  about  to  be  started. 


Section  through  Stope 
Showing  First  Track 


FIG.    153. STOPE  SECTIONS  DURING  EARLY  OPERATIONS. 

The  face  has  previously  been  drilled  up  for  its  full  length.  Stopers  are 
used  for  nearly  all  drilling  in  the  stopes.  When  the  stope  is  thus  "  poled," 
it  appears  as  shown  in  the  second  stage  of  Fig.  151.  The  holes  are  blasted, 
beginning  at  the  raise,  and  the  ore  is  thrown  toward  the  raise,  whence  it  is 
shoveled  into  the  chute.  When  this  first  cut  has  been  carried  so  far  that 
shoveling  becomes  slow,  a  Leyner  or  a  Jackhamer  is  used  to  shoot  up  the 
foot-wall,  making  a  level  cut  about  5  ft.  wide.  This  foot-wall  breaking 
is  done  with  long  " lifters "  or  with  numerous  "  pops"  about  at  right  angles 
to  the  foot- wall;  the  "lifters"  are  also  drilled  with  stoping drills  if  circum- 
stances permit.  On  this  flat  grade,  a  track  is  laid  both  ways  from  the 
chute  and  the  broken  ore  is  handled  with  cars  thenceforth.  A  cross- 
section  of  part  of  the  stope,  Fig.  153  below,  shows  the  poling  and  track. 

A  number  of  cuts  are  started  at  the  raise  and  carried  back  until  the 
stoped  portion  along  the  raise  measures  from  25  to  30  ft.  The  stope  may 
then  look  somewhat  as  in  the  third  stage  of  Fig.  151.  The  ore  is  blasted 


202  DETAILS  OF  PRACTICAL  MINING 

on  steel  sheets  or  on  2-in.  planks,  laid  on  the  tracks  until  some  distance  is 
gained  up  the  dip;  then  raised  plats  are  put  in  as  when  stoping  along  the 
level. 

The  lift  is  then  squared  up  by  carrying  back  each  cut  to  the  limit  of  the 
ore;  the  face  is  drilled  up,  and  poling  again  put  in.  At  the  same  time  the 
Leyner  machine  is  used  to  break  out  a  place  for  a  turnsheet  in  the  raise 
foot-wall  at  the  level  of  the  new  poling  and  a  turnsheet  is  placed  there;  a 
post  to  carry  the  go-devil  blocks  in  the  raise  above  the  turnsheet  is  also 
set  and  the  dumping  device  at  the  chute  top.  The  first  ore  blasted  is 
shoveled  into  cars  fastened  to  the  go-devil  rope  and  then  lowered  and 
dumped.  Stoping  proceeds  away  from  the  raise  as  before  and  when  the 
track  is  installed,  the  cars  are  handled  with  the  go-devil.  The  tracks  and 
ties  from  the  lift  below  are  used  for  the  new  lift. 

This  operation  is  repeated  until  the  oreshoot  in  that  block  is  worked 
out.  Fig.  152  shows  the  appearance  of  a  stope  in  which  six  lifts  have  been 
made.  The  economical  width  of  each  lift,  measured  up  the  dip,  is  calcu- 
lable, being  determined  by  comparing  the  cost  of  installing  the  new  poling, 
track  and  turnsheet,  including  loss  of  time,  with  the  cost  of  shoveling 
down  from  the  face.  The  poling  serves  to  keep  the  broken  ore  at  or  above 
the  track  level,  and  also  acts  as  a  partition  between  ore  and  waste,  the 
coarse  waste  being  thrown  below,  where  it  is  available  for  building  dry- 
wall  supports  to  the  roof  when  desired.  It  must  not  be  supposed  that  the 
stulls  of  the  poling  are  the  only  ones  set.  As  a  matter  of  fact,  stulls  are 
placed  at  frequent  intervals  throughout  the  stope  as  needed. 

The  advantages  of  the  system  as  a  method  of  handling  material  in  a 
flat-dipping  stope  are  numerous:  (1)  It  reduces  to  a  minimum  the  neces- 
sary shoveling.  While  it  is  still  necessary,  as  each  lift  reaches  its  upward 
limit,  to  shovel  the  ore  twice,  this  is  nothing  compared  with  systems  where 
the  muck  may  require  shoveling  over  100  ft.  The  shoveling  is  further- 
more made  easier  by  the  use  of  plats  where  possible.  (2)  It  eliminates 
much  dead  work.  Except  for  the  track  grading  and  occasionally  some 
main-level  chutes,  the  work  is  all  in  the  ore;  no  long  crosscuts  are  run. 

(3)  It  has  great  capacity.     Three  cars  in  a  stope  will  handle  the  product 
of  four  or  five  machines.     Its  capacity  is  especially  noticeable  as  compared 
with  systems  involving  shaking  chutes,  which  were  tried  and  discarded. 

(4)  It  consumes  no  power,  as  does  a  system  involving  hoisting  from  under- 
hand stopes  or  from  workings  down  the  dip;  nor  is  there  any  expense  for  a 
man  on  the  hoist.     (5)  It  is  cheap  in  the  final  results  and  not  so  expensive 
in  material  as  might  be  at  first  supposed,  inasmuch  as  cars,  ropes,  blocks, 
turnsheets,  trucks,  ties  and  poles  are  used  over  again  until  worn  out,  and 
are  often  taken  to  other  stopes.     (6)  It  involves  the  minimum  rehandling 
of  material,  except  at  the  level,  as  compared  with  systems  using  a  series  of 
chutes  down  the  stope  with  intermediate  tramming.     (7)  It  reduces  the 


STOPING  203 

number  of  main-haulage  drifts,  with  a  consequent  reduction  in  develop- 
ment cost,  first  cost  of  bins  and  cost  of  tramming.  (8)  It  has  great 
flexibility.  As  can  be  seen,  it  can  take  care  of  a  stope  of  any  size  or  any 
shape.  By  sending  out  the  lateral  tracks  at  30-ft.  intervals,  the  limits 
of  the  oreshoot  can  be  outlined  exactly.  If,  in  any  case,  the  ore  hooks 
down  into  the  waste  as  shown  at  A,  Fig.  152,  it  is  only  necessary  to  return 
to  one  of  the  lower  levels,  when  the  stope  is  worked  out,  and  continue  it  as 
a  small  drift  so  as  to  tap  the  offshoot  from  below. 

There  are,  however,  certain  disadvantages  and  limitations:  (1) 
Sufficient  headroom  over  the  tracks  is  necessary  to  allow  a  go-devil 
car  with  a  projecting  rock  to  clear  the  roof.  To  obtain  this  means 
considerable  expense  in  cutting  out  the  foot-wall.  The  hanging  is  left 
intact  as  nearly  as  possible.  (2)  It  will  not  operate  below  a  5°  and  with 
difficulty  below  a  10°  dip,  and  conversely  when  35°  is  reached,  its  opera- 
tion becomes  difficult  and  sometimes  dangerous.  (3)  The  slowing  down  of 
operations  and  decrease  of  output  upon  cleaning  up,  beginning  a  new 
lift,  is  a  source  of  trouble  and  makes  it  difficult  to  keep  up  production  if 
several  stopes  are  "moving"  at  the  same  time.  (4)  There  is  some  dan- 
ger of  delay  from  accidents;  the  cars  on  the  incline  may  be  derailed  or  run 
away.  (5)  A  good  hanging  is  a  great  advantage  and  almost  a  requisite. 

In  regard  to  costs:  Where  the  stoping  operations  utilize  the  go-devil 
in  an  old  raise,  the  cost  of  the  go-devil  construction  is  properly  charged  to 
the  original  raising.  The  installation  of  successive  turnsheets,  however, 
involves  breaking  and  replacing  the  old  inclined  track  to  such  an  extent 
that  little  of  it  is  actually  used.  The  cost  of  laying  go-devil  tracks,  as 
with  most  of  the  other  of  these  costs,  will  vary  exceedingly,  according  to 
the  degree  of  uniformity  of  dip,  accessibility  of  working,  height  of  hanging 
wall,  etc. ;  the  labor  cost  varies  from  60  to  80  cts.  per  linear  foot.  The 
cost  of  rail  and  timber  for  a  new  go-devil  will  average  from  50  to  60  cts. 
The  cost  of  the  dump,  bin,  chute,  etc.,  is  similarly  usually  chargeable 
against  the  original  raise  and  when  new  work  must  be  done  for  stoping, 
conditions  are  so  variable  as  to  make  figures  valueless. 

Poling  is  also  subject  to  considerable  variation,  depending  on  the 
accessibility  of  the  stope  and  on  the  width.  The  stulls  are  rounded  on 
the  foot-wall  end  and  are  set  in  hitches.  The  timbermen  who  do  this 
work  are  paid  at  the  rate  of  $3.25,  the  uniform  shift  being  eight  hours. 
Labor  will  vary  from  10  cts.  to  33^  cts.  per  linear  foot.  Material  cost 
will  vary  according  to  the  number  of  old  poles  employed.  A  rough  aver- 
age would  be  25  cts.  per  foot  along  the  stope  for  all  labor  of  setting  stulls 
and  poling. 

Taking  up  the  bottom  for  track  is  also  variable  in  cost.  A  miner 
using  either  a  Waugh,  Jackhamer  or  Leyner  will  shoot  up  from  6  to  10  ft. 
of  bottom  per  shift.  The  machine  costs,  such  as  power,  repairs,  etc.,  will 


204  DETAILS  OF  PRACTICAL  MINING 

be  noted  when  breaking  ore  is  considered.  Explosive  cost  is  low,  as  the 
holes  break  to  good  advantage.  Track  laying  is  rapid  and  cheap. 
Rails  and  ties  from  the  lift  below  are  usually  used.  About  10  cts. 
per  foot  would  cover  the  labor  of  removing  track  from  one  lift  and 
laying  it  on  a  new  grade.  The  total  cost  per  foot  for  the  intermediate  track 
complete  is  about  $1,  and  amounts  to  7  cts.  approximately  per  ton  stoped. 

These  costs  mentioned  cover  preliminary  or  incidental  costs,  dead 
work  in  a  sense.  For  actual  stoping,  although  costs  may  vary  greatly 
with  conditions  in  the  individual  stopes,  more  constant  figures  can  be 
given,  being  obtained  from  totals  of  the  whole  mine  over  considerable 
periods  of  time.  About  seven  tons  per  drill  shift  is  broken  in  stopes. 
The  machinemen  get  $3.  Machine  costs  per  drill  shift  over  the  whole 
mine  are:  Power,  40  cts.;  repairs,  40  cts.;  lubrication,  2  cts.;  and  drill- 
steel  sharpening  and  replacement,  75  cts.  The  amount  of  powder  used 
per  ton  is  1.65  lb.,  with  5.8  ft.  of  fuse  and  0.9  detonators.  A  stope 
hole  breaks  on  an  average  1J^  tons.  The  steel  consumption  using  12  A 
Waugh  stopers  is  2J4  lb.  per  drill  shift. 

The  average  shoveling  rate  in  the  stopes  is  about  7  tons  per  man-shift. 
Two  rates  are  paid  for  shoveling  labor,  $2.50  and  $2.25,  and  an  average 
would  be  about  $2.35,  giving  a  shoveling  cost  of  35  cts.  per  ton.  This  is 
the  total  cost  of  getting  the  material  into  the  main-level  chutes  at  the 
bottom  of  the  stopes,  and  includes  whatever  sorting  is  done  underground. 
The  average  stoping  width  of  the  material  sent  to  the  mill  is  about  4  ft. 

Other  minor  operations  are  involved  in  the  system  of  stoping,  which 
add  to  the  cost,  such  as  setting  the  turnsheet  for  a  new  lift,  setting  the 
go-devil  post  and  block,  etc.  It  should  be  noted  that  the  breaking  and 
shoveling  costs  are  referred  to  the  material  sent  down  the  go-devil,  all  of 
which  goes  to  the  mill.  A  large  amount,  from  10  to  20  per  cent,  of 
the  material  actually  broken,  is  coarse  waste,  which  must  be  handled 
and  which  is  sorted  and  thrown  over  the  poling  in  the  stope;  if  included 
in  the  tonnage  figures,  this  would  boost  appreciably  the  duty  per 
man-shift. 

Methods  and  Costs,  Mother  Lode  Mine,  B.  C.  (By  E.  Hibbert). — The 
system  of  mining  at  the  Mother  Lode  mine  of  the  British  Columbia 
Copper  Co.,  Ltd.,  presents  some  interesting  features.  The  orebody  is  an 
altered  limestone  carrying  enough  gold,  silver  and  copper  to  constitute 
a  low-grade  ore.  It  is  large,  160  ft.  wide  on  an  average,  but  with  a  maxi- 
mum width  of  260  ft.  The  hanging  wall  is  also  an  altered  limestone  but 
carries  practically  no  mineral;  from  the  surface  to  the  200-ft.  level  the 
dip  is  about  70°. 

From  the  60-ft.  level  to  the  surface  most  of  the  ore  was  removed  by  the 
glory-hole  system;  in  places  some  stoping  by  the  shrinkage  system  was 
done  but  proved  dangerous  since  on  blasting  large  pieces  would  rip  off ; 


STOPING 


205 


the  next  system  tried  consisted  of  putting  in  spiral  raises,  the  idea  being 
that  solid  pillars  left  on  the  inside  of  the  spirals  would  support  the 
workings.  In  practice  each  raise,  instead  of  being  a  screw-thread  spiral 


Area 

.  comp/etefy 

mined 
Pillar  ready 
toblast 


FIG.    154. IDEAL    LONGITUDINAL    SECTION    OF    DEVELOPED    OREBODY    SHOWING    ALTER- 
NATING PILLARS  AND  CHAMBERS. 


FIG.    155. FULLY  DEVELOPED  CHAMBER         FIG.    156. CHAMBER  PARTLY  MINED,  SEC- 
READY  FOR  BREAKING  OUT  BENCHES,  SEC-                                 TION  C~D  OF  FIG.   154. 
TION  A-B  OF  FIG.    154. 


FIG.    157. PILLAR   DEVELOPED    READY   FOR   DRILLING    AND   BLASTING.    SECTION   E-F  OF 

FIG.   154. 

presented  somewhat  the  appearance  of  a  screw-thread  stripped  from 
the  screw  and  partly  unraveled.  Mining  difficulties  became  insuperable 
and  the  mine  was  being  cut  up  with  a  series  of  uncoordinated  twisted 


206  DETAILS  OF  PRACTICAL  MINING 

raises  with  branches  and  connections.  Furthermore  all  the  underground 
work  was  done  out  of  the  solid  and  no  advantage  was  taken  of  previous 
workings  as  free  faces  for  breaking  to. 

The  spiral-raise  system  was  abandoned  and  by  straightening  out  the 
raises,  and  then  breaking  down  the  bench  between  the  inclines,  making 
one  incline  or  raise  pass  vertically  over  another  one,  part  of  the  orebody 
was  mined  at  low  cost.  This  idea  was  then  developed  into  what  can  best 
be  described  as  a  pillar-and-chamber  system  of  mining.  An  ideal, 
longitudinal,  vertical  section  of  the  mine  between  levels  with  both  the 
chambers  and  the  pillars  in  various  stages  of  excavation,  is  shown  in 
Fig.  154. 

The  preliminary  opening  up  of  both  pillars  and  chambers  is  not  dis- 
similar. A  foot-wall  raise,  shown  in  Fig.  155,  is  run,  or  an  old  working  is 
used  as  a  raise.  .This  is  not  straight,  but  usually  a  series  of  spirals,  each 
spiral  being  made  from  one  incline  to  that  above  by  partly  cutting  through 
the  pillars  on  each  side  of  the  incline  to  make  the  turn.  From  this, 
inclines  are  driven  to  the  hanging  wall  at  an  angle  of  36°  52',  the  slope 
of  the  ordinary  3:4:5  right  triangle.  Then  in  the  case  of  the  chambers,  the 
benches  or  ribs  between  the  inclines  are  broken  down,  as  shown  in  Fig. 
156,  a  cheap  operation,  as  the  ore  is  bound  on  three  sides  only,  or,  in  the 
case  of  a  first  cut  on  a  bench  of  double  thickness,  such  as  those  in  the 
pillars,  on  four  sides  only.  An  incline  is  prepared  for  benching  by  muck- 
ing off  from  top  to  bottom  and  blowing  off  the  last  of  the  loose  dirt  with 
air,  in  order  that  a  careful  search  for  missed  or  partially  missed  holes  may 
be  made,  partially  missed  holes  being  particularly  liable  to  occur  when 
smooth  slips  are  present  in  the  orebody  and  run  with  the  incline,  but  at  a 
slightly  greater  angle  than  it.  Mining  the  benches  is  comparatively  safe 
as  the  men  are  close  to  the  back  and  can  easily  bar  down  loose  ground. 
Since  a  man,  rolling  from  the  top  of  a  bench,  might  drop  100  ft.  or  more,  it 
is  necessary  to  anchor  both  men  and  tripods  by  ropes. 

The  slope  of  36°  52'  has  proved  the  best  for  getting  rid  of  the  broken 
ore  without  mucking  and  still  maintaining  the  incline  as  flat  as  possible 
for  ease  and  cheapness  in  driving.  To  ascertain  the  right  slope  for  any 
given  orebody,  will  require  some  experimenting.  In  driving  the  incline, 
if  the  slope  is  too  great,  all  the  broken  ore  will  run  down,  leaving  the  bare 
rock  showing  on  the  bottom,  and  if  the  slope  is  too  small,  the  incline  will 
fill  up  with  the  broken  ore. 

In  the  pillars,  the  benches  are  not  broken  down,  and  fewer  inclines 
require  to  be  run,  since  the  thicker  benches  then  left  can  be  drilled  out 
from  the  inclines  above  and  below  the  bench,  as  exhibited  in  Fig.  157,  a 
transverse  section  through  a  pillar.  Mining  the  pillars  constitutes  one 
of  the  interesting  points  of  the  system.  From  the  inside,  the  pillar  is 
drilled  out  from  top  to  bottom,  holes  being  put  in  tops,  sides  and  bottoms 


STOPING  207 

of  the  inclines.  The  standard  length  of  a  hole  is  14  ft.,  although  in  places 
where  such  long  steel  cannot  be  changed,  shorter  holes  are  put  in,  and  in 
other  cases,  where  necessary,  16-ft.  holes  are  drilled.  The  pillars  at  the 
end  of  the  mine  farthest  from  the  shaft  are  first  drilled  and  an  effort  is 
made  always  to  have  several  pillars  drilled  out  ready  for  blasting. 

A  large  porphyry  dike,  20  ft.  thick,  cuts  through  the  orebody  at  the 
200-ft.  level,  the  dip  of  the  dike  being  toward  the  foot-wall  of  the  orebody 
at  approximately  the  same  angle  as  the  inclines.  The  inclines  are  run 
above  the  dike  and  the  pillars  blasted  from  the  dike  to  the  surface,  the 
dike  being  left  intact  so  far  as  possible,  in  order  that  it  may  form  a  roof  for 
the  workings  under  the  200-ft.  level.  In  blasting  the  pillars,  40  per 
cent,  dynamite  is  used  and  all  the  holes  in  a  pillar  are  loaded  and  then 
fired  in  a  mammoth  blast  of  several  hundred  thousand  tons  by  means  of 
electricity. 

The  system  of  mining  described  here  represents  the  ideal  that  has  been 
kept  in  view,  but  owing  to  the  existence  of  old  workings,  it  has  been 
considerably  modified  to  suit  the  conditions.  The  average  costs  per  ton 
for  the  12  months  ending  Nov.  30,  1912,  using  the  system  described,  are 
given  in  Tables  I  and  II. 

The  cost  per  ton  for  explosives  in  a  large  blast  is  small,  but  on  account 
of  the  old  workings  it  has  not  been  possible  to  drill  out  thoroughly  all  parts 
of  a  section,  and  consequently  some  of  the  broken  ore  from  a  large  blast  is 
caved  ground,  which  has  to  be  bulldozed  in  the  chutes  and  block-holed  and 
broken  up  in  the  inclines  leading  to  the  lower  levels.  It  is  in  this  work 
that  most  of  the  explosives  are  used. 

For  the  successful  operation  of  this  method  of  mining,  it  is  considered 
necessary  to  have  a  large,  fairly  uniform  orebody  of  too  low  a  grade  to 
permit  the  use  of  any  filling  or  timbering  method  for  supporting  the 
excavations  made  during  its  extraction.  The  ore  and  walls  must  be  good 
holding  ground,  and  the  foot-wall  dip  at  an  angle  greater  than  36°.  These 
requirements  limit  the  application  of  this  system  of  mining,  but  as  adopted 
at  the  Mother  Lode  mine,  because  of  the  fact  that  the  roof  is  exposed  in 
small  areas  and  the  miner  is  always  close  to  the  back,  it  has  proved  itself 
a  safe  method.  The  low  costs  are  due  to  the  following  causes: 

(1)  Practical  absence  of  mucking. 

(2)  Timbering  required  in  chutes  only. 

(3)  Increased   drilling   capacity   per    machine    when    drilling   out 
pillars,  as  the  machine  has  not  to  be  torn  down  and  stowed  away  every 
day  for  blasting,  but  keeps  drilling  all  the  time;  the  footage  drilled  per 
machine  shift,  using  3j^-in.  machines,  has  risen  from  22  or  23  ft.  to  31  or 
32  ft.  since  this  system  was  adopted; 

(4)  The  exposure  of  free  faces  by  driving  inclines  which  renders  the 
remaining  ore  easier  to  break. 


208 


DETAILS  OF  PRACTICAL  MINING 


TABLE  I. — COSTS  DISTRIBUTED  ACCORDING  TO  OPERATIONS 
Total  shipments 377,510  tons 

Mining :  Cost  per  ton 

Mining  and  timbering  (labor) $0 . 1380 

General  underground  and  tramming  (labor) 0 . 0956 

Explosives 0 . 0997 

Candles. , .  0.0046 

Drill  parts  and  hand  tools 0 . 0210 

Shops  (except  drill  parts  and  hand  tools) 0 . 0063 

Compressor  and  power 0 . 0269 

Lumber 0.0028 

Sundries 0 . 0158 

Total $0.4107 

Hoisting : 

Labor 0 .0339 

Shops  and  sundries 0.0099 

Compressor  and  power 0.0135 

Total .  .   $0.0573 

Crushing,  conveying  and  storage : 

Labor 0 . 0161 

Shops  and  sundries 0 . 0160 

Compressor  and  power 0 . 0033 

Total $0.0354 

Surface  expenses : 

Labor  and  staff  salary 0 . 0244 

Insurance  and  taxes 0 . 0227 

Shops  and  sundries 0 . 0121 

Boilers..  0.0101 


Total..  .  $0.0693 


Total,  f .o.b.   railway  cars  at  mine $0 . 5727 


TABLE  II. — CERTAIN  ITEMS  SUBDIVIDED  INTO  LABOR  AND   SUPPLIES 


Operation 


Cost  per  ton 


Labor 


Supplies 


Total 


Tramming 

General  underground 

Machine  shop 

Blacksmith  shop .... 

Carpenter  shop 

All  shops 


$0.0556 
0.0400 
0.0124 
0.0154 
0.0036 
0.0314 


$0.0071 
0.0044 
0.0012 
0.0019 
0.0002 
0.0033 


$0.0627 
0.0444 
0.0136 
0.0173 
0.0038 
0.0347 


STOPING 


209 


Stoping  Methods  at  the  Golden  Cross  Mine  (By  Andrew  W.  New- 
berry). — The  country  rock,  mica-schist,  at  the  Golden  Cross  mine  in  south- 
eastern California  has  a  fairly  uniform  dip,  varying  from  32°  near  the 


Hanging  nail 


FIG.    158. PLAN    AND    SECTIONS,    SHOWING    RELATIONS    OF    RAISES,    DRIFTS,    CROSSCUTS 

AND  STOPES. 


surface  to  24°  at  a  depth  of  about  1000  ft.  The  deposition  of  the  ore 
followed  certain  layers  which  were  subsequently  faulted  so  as  to  give  the 
impression  of  separate  and  distinct  oreshoots.  The  principal  fault 
planes  are  nearly  vertical  and  approximately  perpendicular  to  the  strike. 


14 


210  DETAILS  OF  PRACTICAL  MINING 

Hence  they  cut  the  orebody  into  blocks  fairly  continuous  on  the  dip. 
Step  faults,  roughly  parallel  to  the  major  fault,  are  not  uncommon. 
These  show  displacements  up  to  12  ft.  with  little  or  no  fault  breccia,  so 
that  their  exact  position  is  often  difficult  to  determine  until  the  ore  is 
found  on  both  sides.  As  the  ore  is  similar  in  appearance  to  the  altered  or 
silicified  country  rock,  close  sampling  is  necessary.  The  occurrence  of 
step  faults  and  their  relation  to  the  major  fault  is  illustrated  in  Fig.  158, 
which  gives  a  section  X-X,  taken  along  the  strike  and  perpendicular  to 
the  dip  of  part  of  the  orebody,  looking  upward  on  the  dip. 

Most  of  the  mining  is  now  carried  on  below  the  600-ft.  level,  where 
the  strata  have  an  average  dip  of  26°,  and  an  average  thickness  of  10  ft. 
and  the  level  interval  in  the  stopes  is  113  ft.  The  method  of  develop- 
ment on  a  typical  level  is  shown  in  Fig.  158.  Section  C  is  first  developed 
by  drifting  along  the  foot-wall;  the  foot  and  hanging  of  sections  A  and  B 
are  then  determined  by  " crosscut  raises"  driven  perpendicular  to  the 
bedding  and  sampled  by  means  of  the  cuttings  from  holes  drilled  with 
stopers.  Section  D,  having  been  proved  on  the  level  immediately  above, 
is  developed  by  a  branch  drift  or  crosscut  from  the  haulage  level  in  ques- 
tion. This  is  best  driven  from  C,  giving  opportunity  to  raise  at  P  and 
possibly  also  at  Q  and  mine  the  upper  part  of  D  through  these  raises.  It 
would  also  be  possible  to  crosscut  from  A  and  shorten  the  tram,  but  this 
would  not  permit  mining  through  P  and  Q. 

Section  A,  which,  on  the  level  in  question,  is  of  greater  importance 
than  B  or  C,  is  developed  in  the  same  manner  as  soon  as  the  foot-wall  of 
the  orebody  has  been  definitely  determined  by  the  crosscut  raise.  That 
portion  of  section  B  which  lies  below  the  crosscut  raise,  would  ordinarily 
be  left  as  a  pillar  until  A  and  C  are  stoped  out.  The  upper  part  of  B  is 
stoped  along  with  A  and  C,  the  broken  ore  going  to  a  chute  which  is  built 
in  the  crosscut  raise,  except  that  portion  to  the  right  of  MN,  which  is 
handled  most  economically  through  the  stope  C,  provided  the  face  of  the 
latter  stope  is  kept  somewhat  in  advance  of  B,  as  stoping  proceeds  up  the 
dip. 

In  the  upper  part  of  the  mine  where  the  dip  of  the  formation  exceeds 
30°,  it  has  been  found  expedient  to  connect  two  levels,  through  the  ore- 
body,  by  means  of  at  least  one  6  X  8-ft.  "dip  raise,"  the  name  locally 
applied  to  a  raise  which  follows  throughout  its  extent  the  dip  of  the  strata. 
The  principal  object  of  such  a  connection  is  to  afford  ventilation.  Of  the 
various  methods  tried  for  the  handling  of  broken  material  on  a  flat  dip, 
the  fixed  steel  chute  was  found  most  satisfactory  and  has  been  adopted 
throughout  the  mine.  The  dry  ore  with  a  considerable  proportion  of 
fines  is  found  to  slide  best  on  a  dip  of  32°.  At  30°,  the  fines  have  a  tend- 
ency to  hang  up  and  block  the  chute,  while  at  34°  the  slide  is  so  rapid  that 
many  of  the  larger  pieces  jump  out.  The  ideal  arrangement  for  long 


STOPING 


211 


chutes  was  found  to  be  a  dip  of  34°  for  the  first  10  ft.,  flattening  gradually 
to  31°,  an  average  of  about  32°.  This  arrangement,  for  obvious  reasons, 
is  only  approximated  in  practice.  With  dips  as  flat  as  30°,  the  raise  is 
begun  at  the  foot-wall  of  the  ore  on  the  lower  level  and  terminated  close 
to  the  hanging  wall  on  the  upper  level,  giving  an  average  inclination  of  32° 
without  breaking  into  the  wall  rock. 

Where  the  dip  of  the  beds  is  less  than  30°,  dip  raises  from  level  to  level 
would  have  added  considerably  to  the  cost  of  mining.  The  scheme  fol- 
lowed is  to  carry  up  the  stope  the  full  thickness  of  the  ore  for  a  distance 
of  60  to  70  ft.,  placing  the  chutes  as  shown  in  Fig.  159,  and  keeping  them 
up  to  within  shoveling  distance  of  the  face.  When  the  stope  has  been 
advanced  to  this  point,  it  is  necessary  either  to  install  some  means  of 


CROSS-SECTION 

PLAN  AND  SECTION  OF  DRIFT  SHOWING  5EGINNIHG 
OF  STOPE  AND  MANNER  OF  PLACING  PISTON  DRIEU 
HOLES 


. 
(  _  {& 


DETAILS  OF  TELESCOPE  CHUTE.LENGTH 

EXTENDED   \7-\l" 


FIG.  159.  -  BEGINNING   OF  STOPE,  STOPE  SECTION  AND  DETAILS  OF  STEEL  CHUTE. 

forced  ventilation,  which  is  done  in  case  the  orebody  is  not  developed  on 
the  level  next  above;  or  better,  to  drive  a  dip  raise  along  the  foot-wall  to 
hole  into  the  drift  on  the  upper  level,  which  is  the  plan  followed  wherever 
possible.  Such  a  raise  is  kept  as  small  as  is  consistent  with  proper  break- 
ing, about  4^  X  6K  ft.  The  broken  ore  is  handled  in  wheelbarrows 
which  are  run  up  on  temporary  ore  fills  and  dumped  into  the  chute. 
As  the  raise  is  advanced,  successive  cuts  parallel  to  EF,  Fig.  159,  are  taken 
off  the  hanging  wall  to  provide  headroom,  part  of  the  broken  ore  being 
left  as  a  temporary  fill.  In  this  way  the  wheelbarrow  runway  is  flattened 
somewhat  and  the  handling  of  the  muck  from  the  dip  raise  is  facilitated. 
Taking  section  C,  of  Fig.  158,  as  an  example,  stoping  is  begun  at  one 
end  and  a  4-ft.  cut  taken  off  the  same  height  as  the  drift,  using  a  one-man 
piston  machine,  the  holes  being  pointed  approximately  up  the  dip.  In 


212  DETAILS  OF  PRACTICAL  MINING 

Fig.  159  is  shown  the  manner  in  which  this  first  cut  is  made.  After  the 
first  cut,  the  piston  machine  is  replaced  by  a  stoper  and  the  ore  next  the 
hanging  broken  on  2  X  12-in.  boards  laid  on  the  track  level.  The  face 
is  then  carried  upward  on  the  dip  full  width  with  a  series  of  cuts  similar 
to  the  first  except  that  the  stoper  is  used.  These  latter  cuts  are  somewhat 
shallower  than  the  first,  averaging  about  3  ft.  3  in.  When  the  face  has 
been  advanced  10  ft.  over  the  full  stoping  length,  a  pair  of  10  X  10-in. 
stulls  is  placed  as  shown  at  R,  Fig.  159.  These  stulls  are  set  5  ft.  10  in. 
center  to  center  and  as  near  the  middle  of  the  stope  as  possible,  allowing 
for  the  pitch  of  the  oreshoot.  Other  stulls,  usually  8X8  in.,  are  placed 
at  intervals  along  the  strike  where  needed. 

When  the  stope  face  has  been  advanced  four  rounds  (about  14  ft.), 
the  bulk  of  the  broken  material  no  longer  falls  on  the  track.  A  steel  chute 
W,  the  details  of  which  are  shown  in  Fig.  159,  then  serves  for  loading  cars. 
The  lower  end  of  the  chute  rests  on  the  edge  of  the  car  and  the  upper  end 
is  either  supported  by  blocks  to  give  the  necessary  inclination  or  suspended 
from  a  plug  in  the  hanging  by  means  of  a  clevis.  In  this  way  the  tram- 
mer can  load  his  own  car.  After  the  next  cut  has  been  made,  the  chute 
V  is  brought  in  and  bolted  inside  of  W  with  four  J^-in.  bolts.  As  the 
face  is  advanced,  the  chute  is  extended  until  the  two  parts  overlap  only 
25  in.,  giving  a  total  length  of  17  ft.  11  in.  Only  one  or  two  telescope 
chutes  are  used  in  a  stope  as  they  are  readily  moved  from  place  to  place. 
To  make  these  chutes,  sheets  of  No.  10  tank  steel  30  in.  wide  by  10  ft. 
long  are  bent  cold  and  drilled  with  J{  Q-m.  and  J^-in.  holes,  spaced  as 
shown.  A  chute  similar  to  type  W,  but  with  the  J^-in.  holes  drilled  at 
each  end  only,  is  used  for  the  fixed  chutes  referred  to  under  dip  raises. 
As  only  one,  or  at  most  two,  stopes  are  brought  in  at  one  time,  four  of  the 
inner  chutes  V  answer  for  the  whole  mine  and  the  bulk  of  the  sheets  are 
made  up  in  form  W. 

While  the  broken  ore  is  being  loaded  by  means  of  telescope  chutes, 
the  two  10  X  10-in.  stulls  R,  Fig.  159,  are  tied  with  a  6  X  8-in.  cross- 
piece  and  long  bolt,  and  a  shoveling  platform  S  is  constructed  of  2-in. 
planking  inclined  downward  toward  the  track  on  an  angle  of  10°.  This 
is  next  covered  with  two  sheets  of  tank  steel  of  the  same  dimensions  as 
that  used  for  the  chutes.  As  soon  as  the  face  has  advanced  too  far  to  be 
reached  by  the  telescope  chute  extended,  the  latter  is  done  away  with, 
and  other  pairs  of  stulls,  U,  are  placed  roughly  in  line  with  R,  and  spaced 
9  ft.  9  in.  center  to  center  on  the  dip;  8  X  8-in.  timber  is  used  in  all  stulls 
except  R.  The  pairs  of  stulls  U  are  connected  with  4  X  6-in.  tiepieces, 
resting  on  2  X  6-in.  blocks  nailed  to  the  stulls,  and  turned  so  that  the 
6-in.  surface  in  each  case  carries  the  two  steel  chutes  TT,  which  are  butt- 
connected  at  these  points;  the  chutes  being  set  at  a  steeper  angle  than  the 
foot- wall,  the  9-ft.  9-in.  spacing  of  the  stulls  accommodates  nicely  the  10-ft. 


STOP  ING  213 


chute  lengths;  40-penny  nails,  driven  through  the  Jf  g-in.  holes  in  the  ends 
of  each  chute,  hold  the  latter  in  place,  and  the  straps  shown  are  bolted, 
like  fish  plates,  both  inside  and  outside  for  greater  solidity.  A  drop  of 
18  in.  is  allowed  between  the  lower  end  of  the  fixed  chute  T  and  the  plat- 
form S.  The  two  lower  chutes  are  set  up  at  an  angle  of  31°  with  the  hori- 
zontal, the  next  two  at  32°,  and  the  fifth  and  last  at  34°. 

As  the  difference  between  chute  and  foot-wall  increases,  shoveling 
becomes  more  difficult.  Moreover,  when  the  face  has  advanced  beyond 
the  reach  of  the  telescope  chute,  a  considerable  proportion  of  the  broken 
ore,  say  60  per  cent,  on  a  stoping  length  of  35  ft.,  must  be  brought  to  the 
fixed  chute  in  wheelbarrows.  The  latter  difficulty  suggests  the  installa- 
tion of  shoveling  platform  and  chutes  in  duplicate,  but  there  is  no  saving 
on  the  stoping  length  assumed.  The  plan  followed  when  the  chute  has 
reached  a  height  of  4  ft.  above  the  foot-  wall,  is  to  lag  against  the  stulls 
the  full  length  of  the  stope  and  allow  the  broken  ore  to  lie  where  it  falls 
until  a  temporary  fill  is  completed  as  shown.  This  serves  as  a  wheel- 
barrow runway  for  moving  the  ore  from  the  ends  of  the  stops.  When  a 
stope  has  been  finished,  these  fills  are  mucked  out. 

The  amount  of  ore  tied  up  in  this  way  is  not  large  until  the  stope  has 
been  advanced  60  to  70  ft.,  and  at  this  point  the  method  is  varied  some- 
what. Stoping  proper  is  stopped  until  the  dip  raise  above  mentioned 
has  holed  through.  As  the  drills  are  operated  only  on  the  day  shift, 
and  the  average  daily  advance  is  2.5  ft.,  this  requires  about  three  weeks. 
Meanwhile,  the  ore  over  the  raise  is  slabbed  off  as  described  under  dip 
raises,  to  provide  headroom,  and  a  narrow  fill  is  made  in  the  space  later 
occupied  by  the  main  waste  fill,  as  shown. 

While  the  dip  raise  is  in  progress,  some  exploratory  work  is  under- 
taken beyond  the  lateral  stoping  limits.  This  generally  takes  the  form 
of  two  sublevel  drifts  K,  one  at  each  end  of  the  stope,  driven  from  a  point 
a  little  above  the  middle.  Such  work  furnishes  material  for  the  main 
waste  fill  which  is  built  up  from  the  ends  of  the  stope  toward  the  dip 
raise  until  it  encounters  the  central  ore  fill.  The  latter  is  then  mucked 
out  and  a  cut  FGH  made  in  the  hanging  wall  about  3.5  ft.  wide  to  provide 
headroom  for  the  dumping  of  wheelbarrows  in  the  upper  part  of  the  stope. 
Holes,  12  to  14  in  number,  drilled  with  the  stoper,  suffice  for  the  hanging- 
wall  cut,  and  the  waste  produced  fills  the  space  previously  occupied  by 
the  last  temporary  ore  fill,  the  width  of  which  is  limited  by  that  of  the 
dip  raise. 

As  soon  as  the  dip  raise  holes  into  the  next  level,  stoping  is  begun 
again,  breaking  toward  the  raise.  Fig.  159  illustrates  this  last  phase. 
It  shows  the  stope  face  advanced  about  25  ft.  along  what  was  previously 
dip  raise,  with  20  ft.  still  to  be  broken.  The  main  waste  fill  is  almost 
completed,  its  final  surface  being  the  dotted  line  //.  Waste  for  this 


214  DETAILS  OF  PRACTICAL  MINING 

part  of  the  fill  may  be  obtained  most  cheaply  from  development  on  the 
upper  level.  The  final  surface,  inclined  at  16°  with  the  horizontal, 
affords  easy  wheelbarrow  grade  from  any  part  of  the  stope. 

The  aplite  dikes  which  are  often  present  in  the  oreshoot  constitute 
a  further  source  of  waste.  This  material,  where  reasonably  hard  and 
unaltered,  may  be  easily  sorted  from  the  broken  ore,  and  used  for  per- 
manent filling  in  place  of  the  temporary  ore  fills. 

Assuming  that  250  ft.  of  drifting  is  necessary  for  the  development  of 
the  blocks  A,  B  and  C,  aggregating  10,000  tons  of  ore  of  which  90  per 
cent,  is  recoverable,  the  development  cost  per  ton  for  drifts  and  cross- 
cuts only,  at  $4.64  per  foot,  comes  to  15  cts.  Adding  to  this  3  cts.  per 
ton  as  the  cost  of  crosscut  raises  and  sublevel  exploration  work,  18  cts. 
per  ton  is  obtained  as  a  fair  estimate  of  development  costs  on  a  block  of 
this  size. 

Where  the  dip  raise  is  not  driven  until  the  stope  has  been  advanced 
over  half  the  level  interval,  its  cost  properly  falls  under  the  head  of  ex- 
traction. In  case  the  dip  raise  is  driven  through  from  one  level  to  the 
next  before  stoping  is  begun,  as  is  done  in  the  more  steeply  dipping  por- 
tions of  the  mine,  its  cost  belongs  to  development. 

An  average  cost  per  foot  for  100-ft.  dip  raises  is  about  $5.40.  Adding 
the  cost  of  two  100-ft.  dip  raises  to  the  development  previously  assumed 
increases  the  development  cost  on  the  9000  tons  recoverable  by  12  cts. 
per  ton,  giving  a  total  of  30  cts.  The  dip-raise  cost  is  entirely  offset  on 
dips  greater  than  30°,  by  saving  in  extraction,  since  one  round  out  of  each 
cut  in  stoping  is  in  effect  a  dip-raise  round,  and  the  work  is  carried  on 
under  better  conditions. 

Allowing  for  the  initial  round  of  each  cut  or  lift  in  stope  advance,  the 
average  break  per  machine  shift  is  a  piece  of  ground  3  ft.  3  in.  by  7  ft.  by 
10  ft.,  or  17.5  tons.  An  average  round  is  nine  3  J^-ft.  holes  with  30  sticks 
of  powder.  The  average  cost  of  extraction  per  ton  for  the  typical  stope 
is  about  $1.07.  distributed  as  follows: 

STOPING  COSTS  PER  TON 

Labor,  breaking. $0. 18  Chutes $0.01 

Labor,  shoveling  at  face 0 . 26  Pipe  and  fittings 0 . 00 

Labor,  loading  cars  and  tramming  .  0.14  Candles  and  lubricating  oil 0 . 03 

Labor,  timbering 0 . 07  Power  and  water 0 . 07 

Labor,  blacksmith 0.04  Drill  repairs 0 . 01 

Explosive 0 . 14  Blacksmith  coal  and  drill  steel  . .  0 . 01 

Timber 0.09  Superintendence 0.02 

These  costs  cover  breaking  and  tramming  only.  No  account  is 
taken  of  hoisting,  sampling,  assaying,  office  expense  or  depreciation.  The 
item  of  superintendence  covers  only  the  foreman's  wages. 


STOPING  215 

Mining  a  Pillar  of  Magnetite. — In  mining  the  deposits  of  magnetite  at 
Mineville,  N.  Y.,  the  room-and-pillar  method  is  adopted.  In  an  excep- 
tional orebody  these  pillars  may  be  trimmed  down  to  a  floor  of  over  100 
ft.  below  the  back.  Often  in  taking  up  lower  levels,  the  pillars  which  are 
started  on  the  floor  above  show  signs  of  weakness,  due  to  seams  and  blocky 
ground,  when  rounded  on  the  lower  levels.  Trimming  the  pillar  or  cut- 
ting away  portions  to  seams  may  make  the  pillar  perfectly  safe.  Again  a 
seam  may  show  which  cuts  across  the  entire  pillar  and  at  such  an  angle 
that  blasting  near  the  ground  will  dislodge  portions  above  the  seam. 

A  particularly  seamy  pillar  in  one  of  the  Mineville  mines  was  taken 
down,  after  it  was  decided  that  the  danger  to  the  miners  working  near 
such  a  pillar  would  be  much  greater  than  working  under  the  greater 
hanging-wall  span  left  after  removing  the  pillar.  To  mine  the  pillar, 
reliable  men  were  selected,  A-frame  staging  and  ladders  were  rigged,  and 
two  roofmen  (working  as  machinemen)  cut  the  ore  away  in  slices  until  the 
pillar  was  lowered  below  the  main  slip.  The  work  was  supervised  by  a 
head  roof  man..  Two  miners  were  kept  near  the  foot  of  the  pillar  under 
cover  of  the  back  of  the  main  haulage  drift.  They  hoisted  drills  and 
water  and  tended  the  guy  and  pulling-back  ropes.  The  miners  on  the 
pillar  worked  with  ropes  around  their  waists.  These  ropes  passed  through 
small  sheave  wheels  held  by  split  eye-bolts  wedged  in  holes  in  the  hanging 
wall.  Several  sheaves,  each  fitted  with  a  %-in.  rope,  were  hung,  and  new 
eye-bolts  were  fastened  to  the  hanging  close  to  the  breast  as  the  cut- 
away advanced.  If  any  fall  from  the  back  had  broken  the  staging,  the 
men  could  have  been  lowered  by  the  miner  at  the  foot  of  the  pillar,  by 
means  of  any  one  of  the  ropes  hanging  from  the  sheaves  hooked  to  the 
eye-bolt. 

The  ropes  served  their  purpose,  for  after  one  of  the  first  blasts  near  the 
hanging  wall,  the  head  roofman  had  climbed  the  staging  to  inspect  and 
had  started  down  the  back  ladder  when  he  heard  the  back  cracking.  He 
climbed  back  to  the  small  bench,  which  had  just  been  made  by  blasting. 
The  fall  broke  the  A-frame  and  ladders  and  he  was  lowered  by  one  of  the 
ropes. 

The  first  drilling  on  the  pillar  was  done  with  a  block-hole  machine; 
after  a  small  bench  had  been  cut  in  near  the  hanging  wall,  a  2%-in. 
piston  machine  was  used.  Blasting  was  done  by  both  fuse  and  battery 
and  holes  were  pointed  in  such  a  manner  that  little  material  went  in  the 
direction  of  the  staging.  Good  judgment  was  exercised  by  the  miners 
in  blasting,  for  until  the  pillar  was  entirely  free  from  the  hanging,  the 
roofmen  left  the  complete  drilling  outfit  on  top  of  the  pillar  during  each 
blast  and  the  machine  was  never  broken,  nor  was  any  part  of  the  staging 
broken  by  blasting,  except  a  few  ladder  rungs.  Before  spitting  the  holes, 
the  rigging  was  pulled  back  some  distance  by  block  and  tackle.  A 


216 


DETAILS  OF  PRACTICAL  MINING 


small  portion  of  the  pillar  came  away  on  the  line  of  the  main  slip  during 
blasting  This  was  fortunate,  for  it  made  the  work  much  safer.  The 
one  block  which  did  slip  off  weighed  approximately  170  tons.  Fig.  160 
shows  approximately  the  order  of  blocks  removed  in  freeing  the  pillar 
from  the  back,  and  also  the  staging  and  equipment. 

In  raising  the  staging,  the  following  was  the  procedure.     A  30-ft. 
ladder  was  raised  and  an  eye-bolt  fixed  at  A ;  6  X  6-in.  stringers,  spliced 


FIG.    160. METHOD  OF  SLICING  A  PILLAR  OF  IRON  ORE,  MINEVILLE,  N.  Y. 

by  2  X  8-in.  plank,  were  then  raised  by  block  and  tackle  hung  to  the 
eye-bolt.  Spliced  spruce  ladders  were  then  raised  on  the  staging  to  a 
point  J5,  where  another  eye-bolt  was  driven.  By  means  of  this  and  block 
and  tackle,  3  X  6-in.  sticks  were  then  raised,  spliced  to  6  X  6-in.  stringers, 
and  then  strutted  with  2  X  8-in.  plank.  From  there  on  ladders  were 
spliced  to  the  bottom  length  of  ladders,  and  the  line  was  drawn  up  to  the 
top  of  the  pillar  by  block  and  tackle  hitched  to  the  2  X  8-in.  braces, 


STOPING 


217 


the  ladders  being  guyed  by  ropes  C  and  D,  and  the  staging  guyed  by  ropes 
E  and  F. 

Top-set  Slicing  on  the  Mesabi  Range  (By  L.  D.  Davenport). — In 
one  of  the  small  mines  of  the  Chisholm  district,  in  Minnesota,  top-set 
slicing  was  tried.  The  ore  in  the  working  place  in  question  extended 
about  21  to  23  ft.  above  the  level  and  to  take  it  out,  the  miners  proceeded 
as  follows:  First  an  open  set  was  put  in  the  drift  using  7-ft.  caps  and 
12-ft.  posts  (sets  1  and  2  shown  in  the  plan  Fig.  161).  Next,  the  slice 
was  extended  along  the  caved  ground  putting  in  7  X  12-ft.  drift  sets 
spaced  about  5  ft.  apart  for  about  25  ft.,  which  was  the  limiting  dis- 
tance on  that  side.  Then  the  ore  above  the  last  sets,  6  and  7,  was  taken 
out  and  7  X  8-ft.  sets  were  put  on  top  of  the  7  X  12-ft.  sets  already  in 
place.  This  top  tier  was  then  worked  back  to  the  open  set.  The  caps 
of  the  bottom  sets  were  framed  on  top  to  make  a  bearing  for  the  posts 
of  the  top  sets.  Seven  sprags  were  used  between  posts  and  caps  of  the 


Caved  Ground 


I 

3 

4 

i 

6 

7 

X 

/  / 

^  Irack- 

„ 

•a. 

„ 

_ 

1 

tfr<? 

9 

5 

Plan  Side    ElevcrHon 

FIG.    161. UNSATISFACTORY  METHOD  OF  TOP-SET  SLICING. 

top  sets  as  shown  in  the  elevation.  The  next  step  was  to  make  room  for 
sets  designated  in  the  plan  as  8  and  9;  this  time,  the  full  height  of  the 
ore  was  taken  out  and  both  top  and  bottom  sets  were  put  in.  In  taking 
out  the  ground  adjacent  to  9,  for  the  next  set,  the  side  weight  of  the 
unsupported  caved  ground  caused  set  5  to  move  and  although  the 
miners  tried  to  hold  it  with  props,  they  could  not  stop  its  moving  and 
the  set  "jacked-knifed,"  the  end  of  the  room  filling  with  sand. 

In  another  similar  room  the  plan  was  tried  of  taking  out  the  top 
set  adjacent  to  set  9  first,  then  putting  in  the  cap  of  the  bottom  set  as  a 
sill  for  the  top  set  and  then  coming  in  under  it  with  the  12-ft.  posts.  This 
method  did  not  seem  to  help  much,  for  as  soon  as  the  second  slice  was 
opened  up  the  whole  room  started  to  move.  As  soon  as  the  posts  moved 
an  inch  or  so,  one  end  of  the  sprags  would  drop  down  and  then  a  little 
working  in  the  caved  ground  would  throw  down  a  set.  In  a  single 
slice  the  top  sets  worked  well  but  in  widening  out  for  the  second  slice, 


218 


DETAILS  OF  PRACTICAL  MINING 


as  soon  as  the  ground  was  relieved  at  the  side  of  a  set,  the  timber  started 
to  move.  It  is  usually  difficult  to  blast  down  a  single  top-set  slice, 
for  even  when  all  the  bottom  posts  are  blasted  the  caps  act  as  stulls  and 
hold  up  the  top  sets. 

It  is  claimed  for  this  system  that  less  timber  is  used  and  that  the 
miners  have  less  shoveling  to  do,  on  account  of  running  the  ore  from  top 
sets  directly  into  the  car,  than  in  taking  the  same  ground  in  two  slices. 


'^mpzm 

i 

Cctved  Ground 
^//////////////^^^ 

® 

® 

3 

® 

4 
® 

5 

® 

6 

© 

1 

\ 
\ 
\ 

L 

152 

14* 

13* 

Drfffi 

FIG.    162. SEQUENCE  OF  SET  REMOVAL    SHOWN    UNSATISFACTORY. 

It  was  found  that  the  amount  of  timber  used  was  about  the  same  with 
the  exception  of  the  boards  used  on  the  bottom  of  the  upper  slice.  The 
miners  stated  that  the  time  saved  in  shoveling  was  more  than  offset 
by  tightening  and  replacing  sprags,  putting  in  props,  etc.  But  the 
most  important  thing  is  the  question  of  the  safety  of  the  men.  A 
regular  10-ft.  slice  is  certainly  safer  to  work  in  than  a  21-ft.  top-set 
slice.  In  this  particular  case,  the  miners  put  up  two  raises  in  the  drift 

Caved  Ground 


29 

25 

1 

3 

4 

5 

6 

7 

© 

© 

<§> 

© 

® 

© 

© 

© 

30 

26 

? 

20 

17 

14 

\\ 

8 

® 

© 

© 

© 

(19) 

(16) 

© 

(10) 

Drift 

PIG.    163. POSSIBLE  IMPROVEMENT  IN  SEQUENCE. 

and  took  out  the  remainder  of  the  pillar  in  two  slices.  They  did  not 
have  to  hoist  the  timber  any  higher  than  in  the  top  sets  and  the  slight 
additional  cost  per  cubic  foot  of  the  top  drift  and  the  raises,  as  com- 
pared with  the  same  amount  of  ore  mined  by  slicing,  was  negligible. 
Also,  the  miners  get  out  a  few  tons  per  day  more  than  with  the  top-set 
slicing: 

Fig.  162  is  a  plan  showing  the  order  in  which  the  sets  were  taken 
out  in  the  working  place  described.     The  plain  figures  refer  to  bottom 


STOPING 


219 


sets,  those  in  rings,  to  top  sets;  and  those  with  superscript,  to  both. 
Fig.  163  shows  a  proposed  method  of  taking  out  the  ground  with  top 
sets,  which  might  work  better,  although  it  has  not  been  tried  here.  After 
putting  in  the  open  sets  1  and  2,  the  bottom  sets  are  taken  out  along 
the  caved  ground  to  the  limiting  distance,  say  to  set  7;  then,  instead  of 
raising  up  and  taking  out  the  top  sets,  set  8  is  cut  in  for  on  the  bottom 
while  18  or  9  ft.  of  solid  ground  above  holds  back  the  caves.  Next, 
set  9  on  top  of  set  7  is  taken  and  then  set  10  on  top  of  set  8.  The  re- 
maining sets  are  taken  out  in  the  order  indicated.  Another  proposed 
method,  which  is  similar  to  that  used  in  square-set  work  in  heavy  ground, 
is  shown  in  Fig.  164.  The  open  sets  1  and  2  are  put  in  the  drift  and  the 
top  set  3  over  2  is  taken  out;  then  set  4  in  the  solid  is  taken  and  the 
top  set  above  it,  etc.,  taking  the  ground  in  vertical  tiers.  As  soon  as 
set  13  is  finished,  the  solid  side  of  the  room  is  boarded  up.  Next,  set 
14  is  taken  out  on  the  bottom  while  the  ground  above  it  steadies  the  caves, 
then  set  15  is  taken  and  at  16  another  bottom  set  started. 

Caved  6rouncf 


1 

1 
1 

1 
1 
1 

1 
1 

1 

' 
• 

18 

0 

16 

14 

© 

© 

4 

© 

6 

© 

8 

® 

10 

I 

Drift 

Plain  Numbers  -  Bottom  Se+s 
Numbers  thus  (7)  =  Top   » 
»            »    1s    —Boih  n 

FIG.    164. PROPOSED  SEQUENCE. 

Successful  Top-set  Slicing  (By  Pomeroy  C.  Merrill). — A  method  of 
top-set  slicing  which  has  been  used  successfully  for  some  years  in  one  of 
the  larger  underground  mines  of  the  Mesabi  range  is  illustrated  in  the 
accompanying  diagram.  It  has  been  used  in  hard  ore,  in  clayey;  wet, 
crushing  ore  and  in  soft  hematite,  under  caved  ground  and  under  sand. 

The  numbers  in  circles  in  Fig.  165  refer  to  the  top  sets  when  the  two- 
set  method  is  used.  In  such  case,  the  order  represented  by  the  figures 
in  the  drawing  is  followed;  the  cut  is  taken  in  for  35  ft.  on  the  far  side  of 
the  room  next  to  the  cave,  removing  lower  sets  only,  and  then  four 
lower  sets  returning  on  the  near  side  are  removed  and  top  sets  are  mined 
in  the  order  shown.  The  room  is  then  carried  back  toward  the  open 
sets  under  50  and  51,  the  miners  keeping  the  bottom  set  of  the  returning 
side  ahead  of  the  top  sets  on  both  sides,  but  sets  52,  53  and  54  are  left 
standing,  and  the  room  is  squared  up,  boarded  and  the  timber  blasted 
out.  The  smaller  room  on  the  other  side  of  the  drift  is  then  mined 
similarly,  In  the  order  shown,  and  the  timber  there  also  blasted  out. 


220 


DETAILS  OF  PRACTICAL  MINING 


In  blasting  down  the  mined-out  rooms,  it  is  seldom  necessary  to  blast 
more  than  the  center  posts  of  the  top  set.  In  this  way  the  room  fills 
before  the  boards  on  the  sides  have  had  a  chance  to  move.  It  is  no 
rare  sight  to  see  every  cap  in  the  bottom  sets  of  the  far  slice  next  to 
the  caved  ground  resting  on  a  post  originally  placed  in  the  near  slice. 
Blasting  is  done  by  battery,  and,  together  with  the  boarding  up,  is  con- 
ducted by  two  blasters  who  go  from  room  to  room  as  required. 

The  advantages  of  this  method  are  that  it  saves  timber,  since  only 
one  post  is  used  in  the  center  and  frequently  old  posts  are  used  on  the 
far  side;  it  saves  shoveling,  the  top-set  ore  being  run  into  cars  through 
board  chutes  which  can  be  quickly  placed  in  any  set;  and  it  is  safe. 


;^^m\\W\m\W^ 


FIG.    165. TOP-SET  SLICING  METHOD  PROVED  SUCCESSFUL. 

Removing  Ore  under  Timbered  Drift  (By  H.  H.  Hodgkinson). — 
Sometimes  it  is  necessary  to  remove  ore  from  under  drift  sets  which 
have  been  loaded  with  rock-filling  on  both  top  and  sides,  and  to  do  this 
without  disturbing  the  set  timbers,  so  that  the  drift  is  still  maintained. 
The  following  method  has  been  used  successfully  and  economically,  not 
only  keeping  the  set  timbers  and  filling  intact,  but  permitting  a  complete 
recovery  of  the  ore. 

On  the  level  below,  set  timbers  with  chutes  were  installed  and  two 
raises,  Fig.  166,  driven  to  the  level  above  at  each  end  of  the  orebody, 
so  as  to  afford  an  entrance  and  exit  to  the  working  place  after  the  chutes 
in  the  sets  were  full  of  broken  ore.  The  ore  was  then  stoped  to  within 
12  ft.  of  the  level  above.  The  stope  was  drawn  and  filled  with  waste 
up  to  within  5  ft.  of  the  back,  a  crib  chute  being  built  as  the  filling 
progressed,  for  handling  the  ore  which  would  be  obtained  by  mining 
the  12-ft.  floor  pillar.  The  fill  was  placed  in  the  empty  stope  by  means 
of  the  two  raises  until  it  reached  its  angle  of  repose,  when  it  was  leveled 
off  to  an  elevation  of  5  ft.  below  the  floor  pillar.  The  remainder  of  the 
fill  was  placed  in  the  stope  by  means  of  a  small  mine  car  which'was  lowered 
down  one  of  the  raises  and  supplied  with  fill  by  a  chute  placed  at  a 
raise  bottom. 


STOPING 


221 


222  DETAILS  OF  PRACTICAL  MINING 

Before  mining  the  floor  pillar  the  three  12-in.  oak  timbers  T,  15  ft. 
long,  were  placed  under  the  caps,  being  supported  by  10-in.  posts,  F, 
as  shown.  Each  of  the  set  sills  was  then  chained  to  the  caps  by  means 
of  5£-in.  iron  chains  made  tight  so  as  to  hold  the  legs  and  sills  of  the 
sets  in  place  while  the  ore  was  being  removed  below.  The  fill  on  the 
sides  of  the  set  timbers  fortunately  was  coarse  rock;  it  was  spiled  off  with 
lagging  each  time  a  sill  was  exposed  and  was  thus  prevented  from  run- 
ning. The  ore  was  mined  from  beneath  two  sets,  these  being  immediately 
supported  by  the  timber  trusses  ABC',  then  the  ore  was  mined  from  be- 
neath the  third  set,  which  was  supported  in  the  same  manner.  These 
timber  trusses  ABC  were  erected  as  soon  as  possible  after  the  sills  were 
exposed,  the  timbers  A  and  B  being  placed  in  hitches  in  the  foot-wall. 
The  timbers  B  were  about  8  or  10  in.  below  the  sills,  to  facilitate  placing 
them  in  position,  the  space  between  them  and  the  sills  being  blocked  up 
tight  by  means  of  the  timbers  M.  As  a  precaution  two  props  were  placed 
under  the  timbers  M  to  relieve  the  timbers  T  of  some  of  their  weight  while 
the  trusses  were  being  framed.  The  timbers  M  were  placed  far  enough 
apart  to  permit  similar  timbers  used  under  the  next  sill  to  interlock 
with  them.  The  broken  ore  was  not  removed  until  the  exposed  sills 
had  been  supported,  and  these  made  a  handy  stage  from  which  to  work. 
After  three  timber  sets  had  been  supported  firmly  by  means  of  the 
trusses,  the  timbers  T  and  V  and  the  chains  were  moved  along  and 
used  to  support  three  more  sets,  the  ore  from  beneath  these  being  re- 
moved as  before.  When  the  ore  had  been  removed  from  below  five 
timber  sets  a  bulkhead  was  built  as  shown  and  the  space  back  of  it 
filled  with  waste. 

TIMBERING  AND  SUBSTITUTES 

Square-set  Timbers  for  Soft  Iron  Ores  (By  L.  D.  Davenport).— 
The  framing  of  square-set  timber  in  the  Chisholm  district  of  the  Mesabi 
range  in  Minnesota,  is  done  by  contract.  Sixteen-foot  round  timbers, 
about  12  to  14  in.  in  diameter,  are  used  for  posts.  These  16-ft.  pieces 
are  cut  in  two  and  framed  on  one  end  for  bottom  posts  and  on  both  ends 
for  top  posts.  The  tenons  are  4  in.  square  and  4  in.  long,  thus  making 
the  bottom  posts  7  ft.  8  in.  from  end  to  shoulder  and  the  top  posts  7  ft. 
4  in.  between  shoulders.  The  caps  are  cut  from  14-ft.  round  timber, 
about  10  to  12  in.  in  diameter.  The  ends  are  flattened  to  9  in.  in  thick- 
ness to  make  a  bearing  for  the  shoulders  of  the  posts.  A  4  X  9-in.  face 
is  left  on  each  end  of  the  cap  to  fit  against  the  tenons  of  the  posts  and 
the  remainder  of  the  end  is  cut  off  at  45°.  The  caps  are  9  in.  thick  and 
the  length  of  the  corresponding  tenons  on  the  posts  is  4  in.  for  each  post, 
which  leaves  1  in.  between  the  ends  of  the  tenons  when  the  timber  is 
first  put  in  place.  This  1-in.  space  is  left  to  allow  the  caps  to  crush  down 


STOPING 


223 


slightly  before  the  tenons  bear  on  one  another.  This  cushioning  effect 
of  the  caps  prevents  the  post  from  splitting  when  the  room  takes  weight. 
As  may  be  inferred  from  the  style  of  framing,  the  most  of  the  weight 
in  the  stopes  comes  from  the  top.  In  Fig.  167  are  shown  the  templates, 
which,  with  an  ax,  adze  and  crosscut  saw,  constitute  the  outfit  of  the 
timber  framer. 


CAP  TEMPLET 


CA,P  TEMPLET 


PIQ.    167.  -  ROUND  SQUARE-SET  TIMBERS  AND  TEMPLATES. 

Square-set  Framing  at  Butte  (Bulletin,  American  Institute  of  Mining 
Engineers).  —  In  the  earlier  operations  in  Butte,  Mont.,  timber  was 
abundant  for  mining  purposes,  and  it  was  common  practice  to  use  sawed 
lumber  for  the  stope  square-setting,  the  framing  on  this  being  rela- 
tively simple.  There  were,  nevertheless,  various  methods  employed  for 
framing  these  square  sets.  In  1,  Fig.  168,  is  shown  the  framing  used  in 
the  High  Ore  mine;  the  post  has  a  long  and  relatively  slender  horn, 
subject  to  breakage  under  heavy  side  pressure,  and  to  crushing  with 
heavy  top  pressure.  The  opposite  extreme  is  shown  in  2,  the  framing 
used  at  the  Syndicate  group.  In  this  case  the  horn  of  the  post  is  only 
1  in.  high,  which  gives  a  small  shoulder  for  the  cap  and  girt.  Further- 
more, the  framing  is  unnecessarily  complicated,  and  consequently 
expensive.  In  3  the  method  for  the  Anaconda  group  is  exhibited. 
It  is  probably  in  general  the  best  method  for  sawed  timber,  being  cheap, 
simple,  and  designed  to  obtain  the  full  strength  of  the  timbers  in  all 
directions.  The  horns  on  the  posts,  being  6  in.  square  by  2  in.,  are 
strong,  and  at  the  same  time  give  a  good  shoulder  for  the  cap  and  the 
girt.  The  caps  butt  end  to  end.  The  girts  in  this  figure  are  unnecessarily 
large,  inasmuch  as  they  lie  parallel  with  the  strike  of  the  deposits  and 
consequently  take  less  weight  than  the  caps,  which  are  subject  to  the 
crushing  force  of  the  hanging  wall.  The  framing  shown  in  4  and  5  is 
similar  to  this,  except  that  the  girts  are  4  in.  less  in  lateral  thickness, 


224 


DETAILS  OF  PRACTICAL  MINING 


TUNNEL  POST-  TUNNEL  CAP  T  STOPE  CAP  6IRT 

Elevation  Side  Elevation  «  5TO£F  PO!'T  Side  Elevation     Side  Elevation 

Side  Llevemon 

H 


Pbtf 


H 


'STEP       DOWN        TIMBER       FRAMING. 

PIG.    168. METHODS    OF   FEAMING    AND    ASSEMBLING    SQUARE    AND    ROUND    TIMBERS   IN 

BUTTE  MINES. 


STOPING  225 

and  so  require  no  framing  at  all,  although  leaving  the  set  just  as  strong. 
One  case  shows  the  dimensions  for  10-in.  caps  and  posts,  and  the  other 
for  12-in.  Using  the  10-in.  timber  the  sets  are  made  5  ft.  from  center  to 
center,  either  cap- way  or  girtway,  and  7  ft.  6  in.  center  to  center  in 
height. 

As  the  timber  about  Butte  available  for  sawing  became  scarcer,  it 
was  found  necessary  to  adopt  round  timbers  underground.  Even  before 
this,  round  timber  had  been  used  by  the  Gagnon  mine.  The  method 
of  framing  employed  here  is  that  shown  in  6.  The  posts  and  caps  have 
horns  5  in.  square  by  2^  in.,  and  the  cap  has  a  shoulder  taken  off  the 
bottom  5  in.  from  the  center  to  allow  it  to  fit  snug  on  top  of  the  post, 
while  on  the  top,  also  5  in.  from  the  center,  a  slab  is  taken  off  for  its 
full  length,  in  order  that  a  stope  floor  may  be  easily  laid.  The  girt  is 
framed  as  shown,  being  usually  less  than  10  in.  in  diameter.  The  sets 
are  8  ft.  3  in.  from  center  to  center  in  height,  and  are  5  ft.  center  to 
center  in  the  other  two  dimensions.  The  framing  used  on  the  levels, 
shown  in  7  and  8,  is  similar,  except  that  the  posts  are  given  a  batter  of 
6  in.,  furnishing  additional  resistance  against  side  pressure. 

A  combination  of  round  and  square  timber  has  been  used  at  the 
Steward  mine  for  a  number  of  years.  The  caps  are  of  square  timber ;  the 
girts  and  posts  are  round.  The  dimensions  and  method  of  framing  are 
shown  in  9,  while  10  and  11  exhibit  the  relations  of  the  level  timbering 
and  the  stope  set.  The  horn  on  the  post  is  1%  in.  deep  on  the  bottom, 
and  3J^  in.  on  the  top,  it  being  supposed  easier  to  stand  a  post  with  a 
short  horn  when  erecting  the  set.  This  necessitates  that  the  horn  of 
the  cap  be  out  of  center;  this  does  not  weaken  the  cap,  but  the  timbers, 
being  unsymmetrical,  are  a  little  slower  to  handle.  The  sets  are  7  ft. 
center  to  center  in  height,  5  ft.  2  in.  center  to  center  along  the  cap,  and 
4  ft.  10  in.  center  to  center  along  the  girt.  The  drift  posts  are  framed 
on  the  top  only,  and  are  given  a  heavy  batter,  which  has  proved  satis- 
factory. In  10  is  also  shown  the  method  of  putting  in  the  sheeting  on 
which  the  waste  is  filled.  The  height  of  this  above  the  drift  cap  allows 
room  for  repairs  when  necessary.  The  material  used  for  this  is  usually 
small  round  timber  or  large  round  timber  sawed  in  half. 

When  round  timber  began  to  be  more  generally  adopted,  the  first 
framing,  done  in  machines,  was  that  shown  in  12,  the  post  having  a  flat 
top,  8  in.  square,  with  no  horn,  and  with  a  miter  cut  to  the  outside  of  the 
timber.  The  caps  and  girts  both  had  horns,  as  shown.  While  this 
style  wa;s  used  for  some  time,  it  was  found  difficult  to  set  the  timbers 
and  to  block  them  so  that  the  sets  would  satisfactorily  resist  pressure, 
and  the  concussion  of  blasting.  The  first  improvement  was  that  shown 
in  13,  a  combination  of  the  square  and  the  beveled  type.  As  can  be 
seen,  the  framing  of  these  caps  is  complicated,  there  being  a  lj^-in. 

15 


226  DETAILS  OF  PRACTICAL  MINING 

shoulder  at  the  base  of  the  horn,  from  which  the  miter  begins.  The 
sets  measure  in  height  7  ft.  5  in.,  and  5  ft.  10  in.  either  cap-way  or  girt- 
way,  in  these  latter  two  cases.  A  still  further  improvement  is  that 
shown  in  14  and  15,  the  step-down  type,  the  large  12-in.  horn  on  the 
post  being  used  when  the  post  is  large  enough.  The  cap  is  slabbed  off 
on  the  top  in  order  to  enable  a  level  floor  to  be  laid.  [The  cap  in  the 
assembled  view,  14,  is  incorrectly  shown  as  a  square  timber. — EDITOR.] 
In  this  style,  the  size  of  the  set  was  also  changed,  it  being  made  7  ft. 
9  in.  in  height  and  5  ft.  4  in.  in  each  of  the  other  dimensions;  being  thus 
smaller  along  the  caps  and  girts,  it  is  stronger,  and  the  common  length 
of  lagging  used,  16  ft.,  will  cut  into  three  pieces  to  fit  the  sets  and  leave 
no  waste.  It  is  probably  the  best  method  of  framing  round  timbers 
where  the  size  varies,  the  full  strength  of  each  member  of  the  set  being 
obtained  regardless  of  the  size  of  the  timber.  If  the  timber  were  all 
the  same  diameter,  a  simpler  method  could  be  used,  somewhat  similar 
to  that  shown  in  3  and  4  for  square  timber. 

On  the  main  levels,  specially  selected  timber  is  used,  varying  from 
12  to  18  in.  in  diameter  for  posts  and  caps.  There  is  no  difference  in 
the  method  of  framing  except  that  the  posts  are  framed  on  one  end 
only.  It  is  the  intention  ultimately  to  apply  this  method  in  all  of  the 
mines  of  the  Anaconda  Copper  Mining  Company. 

Square-set  Timbering  at  Switches  (By  Frederick  W.  Foote). — At 
the  Butte  &  Superior  mine,  Butte,  Mont.,  the  haulage  tracks  in  places 
pass  through  large  stopes  which  require  special  care  in  timbering.  The 
insertion  of  switches  and  curves  was  accomplished,  as  shown  in  Fig. 
169,  without  disturbing  the  general  system  of  timbering  and  without 
bringing  undue  strain  on  any  of  the  parts.  At  the  point  where  the  switch 
or  curve  was  to  be  placed,  a  post  of  the  sill  floor,  and  the  corresponding 
post  of  the  floor  above  were  left  out.  Where  the  top  of  the  upper  post 
would  have  come,  a  block  was  placed.  Four  diagonals  reached  from 
this  block  to  the  tops  of  the  sill  sets.  In  this  way  the  post  of  the  floor 
above  was  supported. 

Supporting  Back  While  Drawing  Shrinkage  Stope  (By  H.  H.  Hodg- 
kinson). — Where  the  shrinkage  system  is  used  for  stoping  and  the  ore 
is  later  drawn  through  chutes  below,  it  is  often  found  necessary  to  timber 
the  back  after  breaking  has  ceased.  In  order  to  obtain  the  maximum 
strength  and  protection  from  the  least  amount  of  timbering  it  is  necessary 
to  frame  the  timbers  in  such  a  manner  that  each  set  conforms  as  nearly 
as  possible  to  the  shape  of  the  ground  and  is  placed  as  close  to  the  back 
as  conditions  will  permit.  A  space  of  at  least  10  in.  must  always  be 
left  between  the  ground  and  these  sets  in  order  to  place  the  lagging  and 
the  blocking;  but  a  greater  space  only  adds  to  the  expense  in  requiring 
extra  blocking,  for  as  a  general  rule  this  space  must  be  blocked  up  tight  to 


STOPING 


227 


hold  loose  ground  in  place.  If  the  ore  is  mined  in  such  a  way  that  the 
back  forms  an  arch,  there  will  be  much  less  weight  upon  the  timbers  to 
support  the  ground  and  the  sets  can  be  placed  farther  apart. 

In  putting  up  a  set,  the  main  timber  is  placed  in  two  hitches,  if 
horizontal,  and  in  one  hitch  with  a  good  head-board  at  the  upper  end, 
if  it  is  a  stull.  It  is  always  best  to  cut  the  timbers  to  fit  the  hitches  and 


FIG.  169. — OBTAINING  BOOM  FOR  TRACK  CURVES  IN  SQUARE-SET  STOPE. 

face  a  timber  off  at  the  point  where  another  timber  rests  upon  it,  for 
the  more  perfectly  the  joints  and  bevels  fit,  the  stronger  is  the  set.  Con- 
siderable time  and  labor  will  be  saved  in  cutting  the  miter  of  two  timbers 
by  bisecting  the  angle  formed  by  them  and  cutting  each  timber  at  a 
bevel  of  that  angle.  This  will  insure  a  much  better  fit  and  a  stronger 
job.  Both  time  and  labor  can  be  wasted  by  cutting  the  bevel  on  one 
timber  and  then  cutting  the  bevel  on  the  other  to  fit.  When  the  bevels 


228 


DETAILS  OF  PRACTICAL  MINING 


on  the  timbers  are  cut  by  the  hit-and-miss  method  each  timber  may  not 
carry  its  due  portion  of  the  load  at  the  miter  and  the  set  is  liable  to  fail 
under  stress. 


FIG.    170.  -  TIMBERING  FOR  CATCHING  UP  STGPE  BACKS. 


The  sets  are  placed  on  from  4J^-  to  8-ft.  centers,  depending  on  the 
conditions,  and  are  braced  against  the  ground.  To  keep  the  miters  from 
pulling  apart,  they  are  also  spiked  with  8-in.  spikes. 

The  style  shown  at  1,  Fig.  170,  is  the  most  desirable,  because  of  the 


STOPING  229 

highly  arched  back  which  permits  placing  the  sets  at  a  greater  distance 
apart.  Three  timbers  are  used  to  make  the  set,  which  conforms  nicely 
to  the  shape  of  the  roof  and  requires  a  small  amount  of  blocking.  The 
horizontal  timber  is  placed  in  a  hitch  at  each  end.  At  2  is  shown  a 
back  highly  arched  as  in  the  preceding  case,  but  with  the  side  A  in  bad 
ground.  Only  one  hitch  is  required  in  this  instance,  with  a  good  head- 
board at  the  upper  end  of  the  stull.  At  3  is  shown  a  stope  whose  back 
is  only  slightly  arched.  Two  hitches  are  required  for  the  timbering. 
At  4  the  back  is  only  slightly  arched,  and  the  wall  at  A  is  assumed  to  be 
bad  and  needs  more  timbering,  although  only  one  hitch  is  used.  The 
back  may  be  highly  arched,  but  due  to  irregularities  in  the  ground  the 
peak  of  the  arch  is  not  in  the  center  of  the  stope.  The  style  of  timbering 
shown  at  5  is  applicable.  At  6  is  shown  a  stope  with  a  back  only  slightly 
arched  and  a  loose  side  at  A.  The  style  of  timbering  at  7  is  adapted  to 
a  stope  with  a  very  flat  back  and  a  bad  side  at  A.  Timbers  placed  as 
shown  at  8  not  only  conform  to  the  shape  of  the  ground,  but  will  support 
heavy  ground.  The  style  shown  at  9  will  support  excessively  heavy 
ground  and  is  so  framed  that  the  miters  bear  their  proper  share  of  the 
burden.  As  a  rule,  if  the  miters  and  hitches  are  properly  cut,  timbers 
for  this  kind  of  work  need  little  bracing.  It  is  poor  practice  to  brace 
one  timber  so  that  the  weight  is  concentrated  on  another  timber,  unless 
the  second  timber  can  be  directly  supported  at  the  point  where  the  load 
is  concentrated. 

The  sides  of  a  stope  may  be  so  bad  as  to  require  timbering  almost  all 
the  way  down  to  the  floor  below.  The  style  used  in  10  will  accomplish 
this  effectively,  each  successive  stull  and  lagging  with  upright  piece  being 
placed  as  the  broken  ore  is  drawn  down.  Each  stull  is  set  in  a  hitch  and 
has  a  head-board  at  the  upper  end. 

Top-slice  Timbering  at  Bingham  (By  D.  W.  Jessup). — The  timbers 
used  in  the  system  of  top-slicing  practised  in  Bingham  Canon,  Utah, 
are  framed  similar  to  those  used  in  the  square-set  system;  their  charac- 
teristics are  shown  in  Fig.  171.  With  the  adjustment  and  settling  of 
the  overburden  the  pressure  on  the  timbers  may  become  enormous,  and 
as  it  is  necessary  to  keep  various  runways  and  connections  open,  the  tim- 
bers supporting  the  runways  must  be  reinforced.  This  is  accomplished 
by  doubling-up  sets,  helping  sets,  angle  bracing,  stulls,  a  tee  piece,  etc. 

The  doubling-up  set,  Fig.  172,  is  a  complete  set  placed  inside  the 
weakened  timbers,  and  consists  of  a  cap  and  two  posts.  The  caps  are 
6X8  in.  and  either  square  or  round  timbers  are  used  as  posts.  The 
helping  set,  Figs.  174  and  177,  is  similar  to  the  doubling-up  set  and  is 
placed  outside  the  failing  set  of  timbers  instead  of  underneath.  This 
set  is  generally  used  for  strengthening,  as  the  weight  falls  more  upon  the 
helping  post  and  less  upon  the  cap,  causing  a  more  nearly  equal  distribu- 


230 


DETAILS  OF  PRACTICAL  MINING 


STOPING 


231 


tion  of  weight.  The  cap  in  the  doubling-up  set  is  often  crushed  and  re- 
quires an  extra  post  in  the  center  which  may  block  the  passageway.  The 
angle  brace  is  used  to  withstand  the  lateral  pressure.  As  the  stope  is 
opened  the  hanging  wall  begins  to  slack  and  swell,  causing  the  timbers  to 
ride  or  move  in  a  horizontal  direction  and  making  the  set  diamond  shaped. 
This  tendency  is  partially  overcome  by  the  angle  brace,  Fig.  173.  The 
brace  is  cut  so  that  the  ends  fit  snug  in  the  corner  formed  by  the  post  and 
cap.  When  the  cap  or  girt  is  breaking  under  pressure  a  stull  is  used  for 
a  temporary  support,  but  if  it  is  to  remain  any  length  of  time  the  stull 
will  probably  buckle  and  the  weight  had  best  be  taken  up  by  a  helping 
set.  In  place  of  a  stull,  a  tee  piece,  Fig.  175,  consisting  of  stull  and  a 


PIG.    177. ISOMETRIC  PROJECTION  TIMBER  SET  AND  HELPING  SET. 

block  or  head-board  is  often  used.  It  is  also  used  to  advantage  wlren  the 
lagging  from  the  floor  above  tends  to  drop  and  cause  a  run  or  deposition 
of  the  overburden.  The  head-board  in  this  case  consists  of  two  pieces 
of  lagging.  Fig.  176  illustrates  angle  sets  used  in  timbering  a  heavy 
hanging  wall.  Often  there  are  odd  corners,  narrow  widths  and  stringers 
of  ore  that  are  mined  from  one  of  the  floors  and  may  be  three  or  four  sets 
wide.  Instead  of  using  the  regulation  timber  set,  a  combination  of  tee 
pieces  is  sometimes  employed  and  gives  good  results,  especially  if  that 
section  of  the  stope  is  not  to  remain  open  for  any  length  of  time.  The 
timbers  are  not  placed  in  any  order  or  system  but  under  the  weakest 
points  of  the  floor  above.  By  this  method  a  great  deal  of  timber  and 
labor  is  saved. 


232  DETAILS  OF  PRACTICAL  MINING 

As  each  successive  slice  is  mined,  the  overburden  becomes  more 
nearly  self-supporting  and  the  mat  of  timbers  forms  a  more  compact 
mass  that  assists  in  supporting  the  overburden  and  thus  causes  less 
weight  to  fall  upon  the  timbers.  This  offers  the  opportunity  for  use 
of  the  tee-piece  system  of  timbering,  and  in  the  future  one  of  the  large 
orebodies  at  Bingham  may  be  mined  by  this  method  instead  of  the  slice- 
set  system.  But  in  most  of  the  orebodies  it  would  not  be  applicable,  as 
the  overburden  is  in  a  fine  state  and  is  constantly  running  down  from 
floor  to  floor,  requiring  closely  laid  flooring  and  substantial  timbering  to 
hold  it  in  check. 

One  of  the  advantages  of  the  top-slice  system  is  that  the  doubling-up 
and  reinforcing  timbers  may  be  of  a  cheap  material.  They  are  not  per- 
manent, being  in  place  merely  for  a  few  days,  perhaps  weeks,  and  odd 
lengths,  sizes  and  nondescript  timbers  can  be  used.  A  large  amount  of 
the  round  timber  is  quaking  asp.  It  is  a  cheaper  grade  than  pine  or  fir, 
possesses  less  compressive  strength  and  does  not  withstand  rot  as  well, 
but  it  gives  satisfaction.  Nothing  smaller  than  a  6-in.  end  is  used  and 
the  bark  is  peeled  to  prevent  rotting.  For  flooring,  odds  and  ends  may 
be  used,  since  the  purpose  is  to  prevent  the  overburden  from  running 
through  into  the  slice  below,  though  a  well-laid  flooring  offers  better 
facilities  for  shoveling.  The  top  of  the  slice  may  or  may  not  need  lagging, 
it  depends  on  the  condition  of  the  flooring  from  the  slice  above,  the  latter 
is  usually  out  of  place  and  is  not  in  position  to  hold  the  overburden.  The 
broken  timbers  in  the  mat  are  constantly  moving  downward  and  exert 
a  great  pressure  on  the  timbers  below,  causing  them  to  break.  These 
projecting  ends  are  sometimes  sawed  or  cut;  if  over  a  post  they  are  blocked 
against  it,  but  never  under  any  circumstances  are  they  blocked  against 
a  cap  or  girt  as  the  pressure  would  cause  them  to  break.  In  blocking 
the  timbers,  the  wedges  are  always  driven  under  the  bottom  and  not  over 
the  top.  When  the  slice  has  been  finished,  a  number  of  unbroken 
timbers  are  removed  and  used  again  in  the  following  slices. 

All  of  the  timbers  are  framed  to  dimensions  in  the  company's  sawmill. 
No  framing  is  done  underground  other  than  an  occasional  butt  cap  or 
short  set.  The  round  timbers  are  from  10  to  20  ft.  long  and  are  cut  to  the 
required  length  by  the  timberman.  The  following  are  the  different- 
sized  timbers  used  in  one  of  the  stopes:  8X8  in.,  39  per  cent.,  for  posts, 
caps  and  girts;  6X8  in.,  5  per  cent.,  for  doubling-up  sets  and  stringers; 
2  X  12  in.,  38  per  cent.,  for  flooring,  side  and  top  lagging;  round,  18  per 
cent.,  for  doubling-up  posts,  stulls  and  cribs. 

Hook  and  Staple  for  Staging. — In  topslicing  on  the  Mesabi,  the  face 
of  the  ore  in  a  room  may  be  as  much  as  14  ft.  high.  To  reach  the  top  of 
this  for  drilling,  a  staging  is  necessary.  The  typical  set  of  timber  con- 
sists of  two  posts  and  a  cap,  with  no  studdle  the  long  way  of  the  room. 


STOPING 


233 


Ordinarily  a  staging  is  built  on  two  pieces  of  lagging  spiked  to  the  four 
posts  of  the  two  sets  nearest  the  face  so  as  to  have  the  direction  that 
studdles  would  have.  Nails  of  30-  or  40-penny  size  are  used  and  are 
left  in  either  the  lagging  or  the  posts  when  the  staging  is  torn  down. 
They  are  a  constant  nuisance  and  source  of  danger,  tearing  the  clothes 
and  skin  of  the  miners. 

Captain  James  Rosewall,  of  the  Harold  mine,  an  Oliver  property, 
devised  a  method  of  eliminating  this  trouble.  He  uses  four  hooks  or 
hangers  of  about  the  design  illustrated  in  Fig.  178,  driving  them  into  the 
post  and  in  them  laying  two  rails  or  poles  on  which  the  staging  is  built. 
Since  there  is  danger  that  the  set  next  the  face  will  fall  out  toward  the 
other  and  there  is  no  studdle  to  prevent,  6-ft.  staples,  also  illustrated, 
are  used  to  drive  into  each  pair  of  posts  in  the  direction  of  the  studdle. 
Since  a  set  of  this  nature  will  last  as  long  as  a  mine,  it  follows  that  its 


PIG.    178. HOOK  TO  SUPPORT  STAGING  AND  STAPLE  TO  STAY  SETS. 

use  is  cheaper  in  the  long  run  than  that  of  nails.  The  staple  is  long 
enough  to  span  the  greatest  distance  between  adjacent  sets  and  by  setting 
it  at  an  inclination  is  available  for  intervals  down  to  4  ft.  It  is  found 
advisable  to  bend  the  drive  points  of  the  hooks  down  from  a  right  angle, 
as  shown,  since  thus  there  is  no  tendency  for  the  weight  of  the  staging 
and  men  to  pull  the  hook  out  of  the  timber.  The  pieces  are  shown  made 
of  %-m.  square  iron;  round  iron  may  also  be  used;  sharp  points  are  rather 
preferable  to  chisel  edges  on  the  ends. 

Building  High  Stages  with  Ladders. — Where  the  walls  of  underground 
workings  are  strong  enough  so  that  they  can  be  left  open  for  long  periods 
of  time,  the  back  is  liable  to  become  bad  and  slab  off;  this  is  true  even 
where  careful  trimming  has  been  done  before  the  ore  was  worked  out. 
It  then  becomes  necessary  to  erect  stages  and  bar  or  blast  down  the  bad 
ground.  Usually  where  there  is  not  much  trimming,  the  back  can  be 


234 


DETAILS  OF  PRACTICAL  MINING 


cleaned  most  satisfactorily  from  stages  built  up  with  ladders  as  legs. 
This  is  the  method  used  in  Michigan  at  the  hard-ore  iron  mines  and  at 
those  copper  mines  where  the  lodes  dip  steeply. 

In  order  to  get  the  most  stable  stage,  one  or  two  ladders  should  lean 
against  one  wall;  but  a  satisfactory  substitute  consists  of  standing  three, 
four  or  even  six  ladders  vertically  on  an  even  base  of  ore  and  building  a 
pile  of  boulders  2  or  3  ft.  high  around  the  bottoms  of  the  ladders.  By 
wedging  the  main  stage  planks  between  the  legs  of  the  ladders  the  whole 
is  tightly  tied  together. 


-24" 


STAGE  DOGS        £      ^K 


Ml 
I 

L 

£ 

Rung,."1* 
Sprctgs 

•«:j 

L 

0          §] 
1           J 

ji 

SPLICED    LADDERS 
FIG.    179. DEVICES  APPLIED  TO  LADDERS  USED  FOR  STAGING. 

Instead  of  wedges  for  binding  the  ladders  to  the  main  or  strap  planks 
that  carry  the  planks  of  the  working  platform,  staples  or  timber  dogs 
are  used  at  the  mines  of  the  Cleveland-Cliffs  Iron  Co.  These  are  made 
of  J^-in.  iron  of  the'  form  and  dimensions  shown  in  1,  Fig.  179.  The 
advantage  of  these  over  nails  is  that  they  tie  the  planks  together  more 
securely  and  also  can  be  taken  out  more  easily  by  means  of  a  pick  or  bar. 
In  order  to  distribute  the  strain  over  several  rungs,  pieces  of  1  X  3-in. 
plank  with  a  notch  at  each  end,  cut  just  long  enough  to  fit  snug,  are  driven 
in  as  sprags  next  to  each  leg  between  several  sets  of  rungs,  as  shown  in 
2.  In  this  way  danger  from  the  rungs  of  the  ladders  giving  away  under 


STOPING  235 

the  weight  of  the  stage  is  minimized.  Often  a  stage  has  to  be  built  to 
reach  a  back  30  ft.  high  or  more.  As  mine  ladders  are  rarely  over  16  ft. 
long,  it  then  becomes  necessary  to  splice  them  together.  Side  cleats 
can  be  nailed  to  the  legs  for  this  purpose,  but  a  much  more  secure  and 
handy  method  is  by  the  use  of  U-bolts,  shown  detached  in  3  and  applied 
in  4.  The  bolt  is  made  of  J£-in.  iron  with  a  plate  or  double  washer  of 
H  X  lK-in.  iron. 

Hook  for  Hauling  Timbers. — The  accompanying  illustration,  Fig. 
180,  shows  a  simple  hook  that  may  be  quickly  attached  or  detached  from 
the  hoisting  rope  in  moving  timbers  through  a  drift  or  up  a  winze. 
The  device  consists  of  hook  and  link,  the  back  end  of  the  hook  being 
enlarged  and  toothed,  so  as  to  act  like  a  cam  with  reference  to  the  hole  for 
the  link.  When  the  rope  is  passed  through  the  link  and  the  hook  is 
straightened  by  the  load,  the  toothed  cam  seizes  the  rope  and  pressing 
it  against  the  link  holds  it  tight  until  the  load  is  released  or  the  hoisting 
rope  is  slacked  off.  This  hook  can  be  attached  or  detached  quickly  and 
in  some  places  will  prove  to  be  more  convenient  than  the  slower  method 
of  tying  hitches  or  knots. 


FIG.    180. — ROPE-GRIPPING  HOOK  FOR    HANDLING   TIMBER. 

Concrete  Bulkheads  for  Pillar  Extraction  (By  Temple  Chapman). — 
The  soft-ground  mines  of  the  Joplin  district  are  worked  by  a  system  which 
involves  leaving  a  large  portion  of  the  ore  in  the  form  of  pillars  to  be 
extracted  later.  The  profitable  extraction  of  the  pillars  is  a  serious  prob- 
lem. From  one  soft-ground  mine  as  an  example,  where  the  ore  remaining 
in  pillars  was  believed  to  be  equal  in  value  to  that  already  taken  out,  the 
profit  on  the  half  of  the  orebody  first  mined  was  $200,000,  while  on  the 
second  half  of  the  ore,  that  which  was  left  in  pillars,  it  was  only  about 
$20,000.  The  reason  for  the  poor  profit  from  the  pillars  was  due  to 
several  circumstances :  The  caving  of  the  ground  mixed  together  pay  ore 
and  waste  rock;  heavy  and  costly  timbering  was  made  necessary  in 
mining  the  pillars  because  of  the  weight  and  pressure  of  the  caved 
ground;  much  rich  ore  was  lost  in  the  caved  mass  of  ore,  soapstone,  rock 
and  mud.  Big  pens  of  oak  logs,  built  at  heavy  cost,  were  crushed  flat 
and  mashed  like  matches  by  the  enormous  weight  of  the  ground.  To 
have  sunk  the  shafts  deeper  and  drifted  out  under  all  the  pillars  through 
barren  rock  would  have  cost  thousands  of  dollars  and  would  have  re- 


236  DETAILS  OF  PRACTICAL  MINING 

covered  only  part  of  the  ore,  and  that  mixed  with  much  waste,  mud  and 
rock. 

In  the  Longacre-Chapman  mine  at  Neck  City  and  the  Century  mine 
adjoining,  a  situation  existed  similar  to  that  just  described,  about  half 
of  the  ore  being  left  in  big  pillars  of  considerable  value.  To  attempt 
extracting  these  with  no  other  support  than  ordinary  timbering  and  pen- 
ning would  have  allowed  the  ground  to  cave,  jeopardizing  both  the 
miners  and  the  ore.  Log  pens  and  timbers  where  the  drifts  are  30  to  40 
ft.  high,  have  generally  failed  to  hold  up  the  ground  after  the  pillars  have 
been  cut  out.  Nor  are  log  pens  of  such  size  at  all  cheap  to  put  in.  The 
cost  of  both  logs  and  labor  counts  up  fast.  Therefore,  an  attempt 
was  made  to  support  the  roof  in  the  following  manner:  Holes  were 
drilled  between  pillars  from  the  surface  of  the  ground  to  the  roof  of 
the  drift  below,  6-in.  drill  casing  being  left  in  each  hole.  Forms  for 
concrete,  about  15  ft.  square,  wired  across,  were  being  built  under  each 
drill  hole.  Tailings  and  water  happened  to  be  conveniently  situated 
within  a  few  feet  of  the  tops  of  the  drill  holes  and  cement  bought  in  car- 
load lots  was  distributed  at  the  rate  of  200  bbl.  for  each  pen. 

A  contractor,  with  a  gasoline-engine-driven  concrete  mixer,  mixed 
the  concrete  on  top  and  poured  it  down  the  drill  holes.  A  man  stationed 
in  each  form  below  spread  and  tamped  the  concrete  as  it  came  down 
the  hole.  Empty  powder  boxes  were  set  in  the  concrete  near  the  top, 
several  on  each  side;  these  served  as  hitches  for  timber  caps  reaching 
from  one  concrete  pen  to  another.  These  timbers  caught  up  the  roof 
between  pens  and  could  be  additionally  supported  by  posts  set  under  their 
middle  points. 

There  have  been  built  six  of  these  pillars.  They  average  40  ft.  in 
height  and  16  ft.  square.  Sixty-pound  T-rails  set  in  the  cement  were 
carried  from  the  top  of  one  pillar  to  the  top  of  the  next  pillar,  about  25  ft. 
away,  in  addition  to  the  timbers  set  in  the  hitches.  Cordwood  was  filled 
in  above  the  timbers  and  the  T-rails,  the  latter  being  braced,  thus  making 
a  wide  support,  both  the  roof  over  the  pillars  and  the  roof  between  them 
being  held. 

Old  screen  jackets  were  cut  into  slices  10  ft.  long  by  6  in.  wide,  and 
used  for  reinforcement.  These  strips  were  laid  in  the  cement  east  and 
west,  about  6  in.  apart.  Then  a  foot  higher  up  they  would  be  laid  north 
and  south.  The  piers  increased  about  6  ft.  in  height  each  day,  the  pre- 
vious day's  mixture  being  pretty  well  set  by  the  next  morning.  The  boards 
for  forms  were  all  recovered  after  each  pillar  was  completed.  When  the 
pillar  got  up  to  35  ft.,  or  within  5  ft.  of  the  roof,  the  roof  was  carefully 
trimmed  and  left  a  little  high  where  the  drill  hole  came  through.  The 
last  cement  would  then  be  mixed  a  little  richer  and  wetter  and  would  fill 
every  space  up  tight  to  the  top. 


STOPING  237 

FILLING 

Sand  Filling  at  Cinderella  Consolidated  (Institution  of  Mining  and 
Metallurgy). — The  system  of  sand  filling  of  stopes,  devised  by  Mr. 
Girdler-Brown,  of  the  Cinderella  Consolidated  mine,  in  the  Transvaal, 
compares  favorably  in  first  cost  with  any  other  method,  no  dewatering 
cones  or  neutralization  process  being  necessary.  It  shows  to  greatest 
advantage  when  employed  in  shafts  of  great  depth  and  under  circum- 
stances such  that  continuous  filling  is  not  necessary,  as  interruptions  are 
almost  certain  to  occur  from  time  to  time  in  wet  weather,  due  to  an  excess 
of  moisture  in  the  sand. 

The  sand  used  should  not  contain  over  5  to  6  per  cent,  of  moisture, 
and  should  have  been  exposed  to  the  sun  and  air  for  at  least  two  days 
before  being  used.  It  will  then  be  practically  free  from  cyanide  and 
neutral  in  character.  Sand  taken  directly  from  the  cyanide  tanks  was 
tried  for  this  process,  but  even  after  it  had  been  treated  with  potassium 
permanganate,  considerable  quantities  of  cyanogen  were  evolved  when 
the  sands  became  mixed  with  acid  mine  water.  This  action  was,  how- 
ever, entirely  obviated  by  exposing  the  sand  to  the  sun  and  air,  as  al- 
ready mentioned.  Plans  were  originally  laid  out  to  follow  the  usual 
practice  in  sand  filling  of  running  the  sand  down  the  shaft  mixed  with 
water,  but  this  idea  was  found  to  be  impracticable,  owing  chiefly  to  the 
excessive  wear  of  the  pipe  caused  by  the  great  depth  to  which  the  mixed 
sand  fell  and  the  cost  of  pumping  entailed.  When  the  column  first 
installed  was  worn  out,  it  was  replaced  by  a  square  wooden-box  launder, 
down  which  the  sand  fell  unmixed  with  water.  The  launder  measured 
11  X  12  in.  in  cross-section,  and  its  cost  was  approximately  61  cts.  per 
running  foot.  Observation  doors  were  cut  at  distances  of  about  100  ft. 

The  piping  and  launder  from  the  surface  bins  were  replaced  by  a 
belt  which  conveyed  the  sand  to  the  top  of  the  box  launder.  It  was 
found  that  sand  containing  not  over  4  per  cent,  of  moisture  would  run 
freely  from  the  bins  to  the  belt  without  handling.  On  arriving  at  the 
head  of  the  launder,  the  sand  falls  down  the  box  to  a  steeply  inclined  iron 
plate,  over  which  a  stream  of  water  is  made  to  play.  The  plate  should 
be  provided  with  a  liner  of  the  hardest  white  cast  iron  to  counteract  the 
excessive  wear  at  the  point.  After  being  mixed  the  sand  and  water 
flow  into  a  steeply  inclined  launder,  where  they  undergo  further  mixture 
before  being  conveyed  by  pipes  or  launders  to  the  part  of  the  mine 
requiring  filling.  The  layout  is  shown  in  Fig.  181. 

The  effective  capacity  of  the  plant  is  controlled  by  the  quantity  of 
water  available,  as  it  is  found  that  the  delivery  of  the  sand  to  the  vertical 
box  is  practically  without  limit.  In  the  Cinderella  plant,  experience 
shows  that  the  box  launder  has  not  appreciably  worn,  the  reason  for 


238 


DETAILS  OF  PRACTICAL  MINING 


this  being  the  conduct  of  the  sand,  which  travels  normally  down  the  center 
of  the  box  with  little  or  no  impingement  on  the  side.  This  was  proved 
by  examination  through  the  observation  doors  alluded  to.  The  sand 
could  be  seen  falling  in  a  steady  stream,  the  bare  hand  could  be  held  in 
the  corner  of  the  box,  but  it  was  difficult  to  hold  an  iron  bar  across  the 
falling  sand  at  the  middle  of  the  launder  and  the  metal  was  quickly 
polished  by  the  rapidly  moving  particles.  It  was  noticed  that  the  falling 


FIG.    181. LAYOUT  FOR  DRY-SAND  FILLING  SYSTEM. 

stream  of  sand  created  a  suction  down  the  launder;  thus,  on  opening  an 
observation  door,  no  sand  escaped,  but  air  was  drawn  in. 

From  time  to  time  trouble  was  caused  by  sand  containing  too  great 
a  percentage  of  moisture.  This  caused  it  to  adhere  to  the  sides  of  the 
launder  in  gradually  increasing  quantities,  until  at  last  the  flow  was 
seriously  impeded.  Under  such  circumstances  the  remedy  was  to 
flush  out  the  box  with  water  from  the  surface  until  the  adhering  sand  was 
washed  away.  In  this  connection,  experiments  were  conducted  with 
a  view  to  determining  the  maximum  percentage  of  moisture  which  would 


STOPING  239 

allow  the  sand  to  run  down  "dry."  The  following  were  the  results: 
Up  to  5  per  cent,  moisture  the  sand  fell  freely,  leaving  the  sides  of  the  box 
clear  and  dry.  From  5  per  cent,  to  7  per  cent,  of  moisture  did  not  affect 
the  fall,  provided  that  the  sides  of  the  box  were  themselves  dry.  "From 
7  per  cent,  to  9  per  cent.,  the  sand  gradually  became  adhering  to  the  sides 
of  the  launder  where  it  accumulated  slowly.  From  9  per  cent,  up  of 
moisture  caused  a  rapid  accumulation  of  sand  along  the  sides  of  the 
launder.  The  results  were  largely  influenced,  it  .was  found,  by  the  pro- 
portion of  slime  contained  in  the  sand. 

The  liability  of  the  sand  to  choke  the  launder  under  certain  adverse 
conditions  renders  it  essential  to  have  an  efficient  bell-signaling  service 
between  the  mining  point  and  the  furthest  bin,  so  that  the  supply  of  sand 
can  be  regulated  in  proportion  to  the  quantity  of  water  available  for 
service,  since  if  the  sand  is  supplied  too  quickly,  it  has  the  tendency  to 
pile  up  at  the  bottom  of  the  box  launder  and  choke  it.  On  the  other  hand, 
if  the  sand  appears  to  be  coming  down  slowly,  it  may  be  that  a  certain 
proportion  is  sticking  to  the  sides  of  the  launder  on  account  of  there  being 
too  great  a  percentage  of  moisture.  When  this  is  found  to  be  the  case, 
flushing  must  be  resorted  to. 

Numerous  efforts  were  made  to  use  the  current  sand  production  direct 
from  the  cyanide  tank  with  a  view  of  saving  transportation  from  the 
dumps.  It  was  found,  however,  that  this  sand,  which  contains  from  12 
to  15  per  cent,  of  moisture,  gave  constant  trouble  by  adhering  to  the 
sides  of  the  launder,  forming  an  accumulation.  These  accumulations 
happened  at  various  points  down  the  launder,  but  principally  at  one  point 
about  600  ft.  down.  Jets  of  compressed  air  were  introduced  with  a  view 
of  increasing  the  velocity  of  the  falling  stream,  and  thus  preventing  the 
adhesion  of  the  sand.  The  box  launder  was,  furthermore,  connected  with 
the  intake  of  the  ventilating  fan  near  the  bottom,  and  to  a  Roots  blower 
at  the  top,  the  idea  being  to  dry  the  sides  of  the  box  and  thus  prevent  the 
sand  from  sticking.  These  devices  undoubtedly  permitted  the  use  of 
damper  sand  than  could  otherwise  have  been  employed,  but  they  were 
practically  of  no  avail  when  the  sand  carried  over  10  per  cent,  of  moisture, 
and  were  consequently  abandoned  after  prolonged  trial. 

It  was  found  necessary  to  place  the  box  launder  in  the  upcast  side  of 
the  shaft  and  in  the  same  compartment  with  the  pump  column;  con- 
sequently the  box  was  always  wet  on  the  outside  and  water  constantly 
reached  the  interior.  The  sand  containing  not  over  4  per  cent,  moisture 
does  not  give  rise  to  any  considerable  trouble,  especially  if  the  launder 
has  its  interior  surface  plain  and  smooth  and  the  outside  tarred.  With 
sand  containing  up  to  a  maximum  of  8  per  cent,  of  moisture,  the  launder 
should  be  placed  in  the  driest  compartment  available  on  the  downcast 
side. 


240  DETAILS  OF  PRACTICAL  MINING 

There  is  actually  a  saving  in  the  quantity  of  water  required  to  be 
pumped  out  of  the  mine  when  the  sand-filling  plan  is  in  operation.  The 
sand  in  the  stope  probably  retains  at  least  10  per  cent,  of  water,  the  sand 
as  sent  down  contains  on  an  average  3  per  cent.,  and  it  is  calculated  that 
in  the  course  of  a  good  day's  run  the  water  saved  from  being  pumped 
4000  ft.  to  the  surface  will  amount  to  about  8000  gal. 

The  labor  required  to  operate  the  plant  is  small,  a  subforeman  in 
charge  of  three  boys  will  look  after  the  belt  and  surface  bins,  and  the 
underground  part,  including  the  mixing  point  and  the  stope  to  be  filled, 
is  in  charge  of  the  timberman.  The  sand  is  brought  from  the  dump  to 
the  surface  bin  by  means  of  mechanical  haulage,  the  actual  shoveling 
and  tipping  necessary  being  done  by  unskilled  labor.  On  an  average  of 
400  tons  per  shift,  the  cost  was  5.23  cts.  per  ton. 

Bore -hole  System  of  Sand  Filling  (Journ.,  Chemical,  Metallurgical 
and  Mining  Society  of  South  Africa). — The  transfer  of  sand  filling  under- 
ground through  bore  holes  has  proved  successful  on  the  Rand  in  two 
mines,  the  Robinson  Deep  and  the  Simmer  &  Jack.  The  essential  fea- 
tures of  the  system  at  the  Simmer  &  Jack  consist  in  mixing  the  sand 
residue,  immediately  after  car  discharge  from  the  vats,  with  water  and  a 
small  amount  of  permanganate  of  potash  solution;  and  pumping  the  mix- 
ture through  pipes  to  dewatering  diaphragm-cone  classifiers  placed  imme- 
diately above  the  bore  hole  or  other  point  of  lowering,  down  which  the 
thick  sandy  underflow  continuously  descends.  The  fluid  cone-overflow 
gravitates  or  is  pumped  back  to  the  mixing  box  beside  the  pump,  into 
which  the  residue  is  dumped,  thus  completing  its  circuit  and  serving  to 
transport  more  residue.  The  underflow  falling  down  the  bore  hole  into 
the  mine  is  then  conveyed  by  launder  to  the  stope  to  be  filled,  where  it 
speedily  drains,  leaving  a  solid  mass  of  sand  behind.  Any  accidental 
filling  of  the  hole  with  sand  is  of  temporary  inconvenience  only,  as  the 
turning  in  of  a  small  stream  of  water  at  the  top  in  the  evening  will  result 
in  a  clearance  by  the  following  morning. 

Distinctive  features  of  the  system  are :  That  it  is  applied  to  current 
residue;  that  the  residue  is  transported  from  the  sand  plant  to  the  lower- 
ing point  as  a  flowing  pulp  and  not  by  cars,  the  water  performing  a  cir- 
cuit; that  the  lowering  proceeds  continuously  instead  of  intermittently, 
and  is  usually  performed  by  passing  a  thick  pulp  through  a  bore  hole  in- 
stead of  a  more  fluid  pulp  through  pipes,  thus  avoiding  wear  of  the  latter; 
and  that  distribution  of  the  sand  underground  is  carried  out  in  open 
launders  instead  of  in  pipes  under  pressure.  One  portion  of  the  Simmer 
&  Jack  mine  requiring  filling  happens  to  be  nearly  below  the  sand  plant; 
so  an  8-in.  hole  500  ft.  deep  has  been  put  down  near  the  residue  car  track, 
and  a  short,  steep  tunnel  from  the  mixing  box  to  the  hole  allows  the  residue 
there  dumped  to  be  carried  by  a  small  stream  of  water  as  a  thick  pulp 


STOPING 


241 


into   the   mine,  without  the  need  of  pumping  and  dewatering.     This 
modification  has  been  more  fully  developed  on  the  Robinson  Deep. 

The  main  features  of  the  surface  arrangements  at  the  Simmer  & 
Jack  are  clearly  shown  in  Fig.  182.  This  outcrop  mine  extends  over  a 
large  area  and  has  been  worked  for  many  years.  It  was  hence  desirable 
and  economically  practicable  to  lower  sand  at  several  points,  and  the  con- 
tingency of  employing  other  points  in  the  future  had  also  to  be  borne  in 
mind.  Under  these  conditions  part  of  the  sand  from  the  residue  cars  is 
periodically  gravitated  as  a  pulp  from  the  mixing  box  F  down  the  tunnel 


To  Dump 


~  i'iKO'  Rising  Grade 

"Z4^r^~6*0verf low  return  pip.  from 
-- — --..pump  te  mixing  bm 


Four  Dewatering  Cones, 

8'Dia  10'Decp 
/Vbove  8'  Borehole,n6'Deep. 


ewaering 
8'Dia.  10' Deep       . 
Delivering  underflow  to 
Inclined  Shaft 


FIG.    182. SURFACE  ARRANGEMENTS  AT  SIMMER  &  JACK. 


./•    * 
Four  Dewatering  Cones. 

8'Dia.  10' Deep- 
Delivering  underflow 
to  borehole. 


and  hole  D,  put  down  for  this  purpose.  The  remaining  sand  is  pumped 
as  a  pulp  to  points  A,  B  or  C.  From  A  the  cone  overflow  gravitates 
back  to  the  mixing  box  E,  15  ft.  long,  8  ft.  wide  and  6  ft.  deep  with  a 
steeply  inclined  bottom,  beside  the  residue  track,  although  the  tops  of 
the  cones  at  A  are  at  ground  level  to  saving  pumping  head.  The  cones 
at  B  and  C  are  above  ground,  as  their  location  necessitates  return  by 
pumping  of  the  overflow  to  the  mixing  box.  The  graded  launder  about 
20  ft.  long  between  the  mixing  box  at  E  and  the  pumps,  serves  as  an 
automatic  regulator  of  the  consistency  of  pulp  entering  the  pumps  and 
prevents  the  latter  from  being  choked,  as  extremely  thick  pulp  will  not 


242 


DETAILS  OF  PRACTICAL  MINING 


flow  down  this  launder.     The  empty  cars  in  every  case  return  to  the 
sand  plant. 

As  the  local  conditions  at  the  Robinson  Deep  are  different,  it  was 
decided  after  consideration  to  modify  the  system  somewhat.  The  greater 
depth  and  smaller  area  of  the  mine  rendered  it  both  advisable  and  prac- 
ticable to  restrict  permanently  the  lowering  to  one  point  at  the  north  of 
the  property,  Fig.  183.  A  bore  hole,  decreasing  from  10  in.  diameter  at 
the  top  to  7  in.  diameter  at  the  bottom  and  1729  ft.  deep,  was  accordingly 
put  down  so  that  all  worked-out  stopes  could  be  served  from  it  by  pulp 
gravitation  underground,  and  as  the  upper  end  of  the  bore  hole  was  18 
ft.  higher  than  the  track  under  the  sand  vats  and  a  considerable  distance 
away,  it  was  decided  to  drive  a  4 J/£  X  6-ft.  tunnel  from  the  sand  plant  at 
a  dip  of  20°.  This  tunnel  was  1125  ft.  long  and  intersected  the  bore 
hole  at  390  ft.  from  the  surface,  so  that  a  thick  pulp  could  be  gravitated 


Sand  Vats 


FIG.  183. SECTION  THROUGH  TUNNEL  AND  BOREHOLE  AT  ROBINSON  DEEP. 

direct  from  the  sand  plant  through  the  tunnel  and  bore  hole  into  the  mine 
without  the  need  of  pumping  or  de watering  the  pulp.  The  open  end 
of  the  tunnel  is  directly  under  the  residue  track  and  just  clear  of  the  vats 
so  that  the  residue  after  dumping  from  trucks,  and  receiving  the  addition 
of  a  small  stream  of  water  and  permanganate  solution,  descends  as  a  28 
per  cent,  moisture  pulp  till  it  comes  to  rest  in  the  desired  stope  under- 
ground. This  installation  cost  a  good  deal  more  in  capital  expenditure 
upon  the  tunnel  than  the  Simmer  &  Jack  installation  of  surface  pumps, 
pipes  and  cones  for  a  lowering  point,  but  is  preferable  under  the  conditions 
indicated  and  has  the  advantage  of  low  surface  operating  costs,  these 
being  merely  the  short  car  transport  of  residue  from  vats,  tipping  and 
returning  the  trucks,  and  the  addition  of  a  little  permanganate.  A 
screen  of  vertical  grizzly  bars  across  the  tunnel  prevents  the  bore  from 
being  choked  by  foreign  substances.  The  amount  of  drainage  water  to 
be  pumped  to  the  surface  from  underground  involved  in  sand  filling 


STOPING  243 

with  so  thick  a  pulp  is  small,  amounting  only  to  about  a  quarter  of  a 
fluid  ton  per  ton  of  dry  sand  deposited,  or  50,000  gal.  daily,  with  a 
monthly  ore  tonnage  milled  of  60,000  tons. 

In  the  operations  of  sand  filling,  the  permanency  of  the  underground 
barriers  must  be  considered.  If  there  is  a  possibility  of  water  finding 
its  way  into  the  filled  area,  it  will  not  be  sufficient  to  construct  a  barrier 
to  last  little  longer  than  the  period  of  filling  and  drainage.  Such  water, 
except  perhaps  in  the  case  of  flat  workings,  would  in  time  wash  down  the 
sand  through  any  perished  parts  of  the  barrier  into  the  lower  parts  of  the 
mines.  The  construction  of  a  permanent  barrier  is  costly,  but  on  many 
mines  dikes,  faults  and  unpayable  bodies  of  ore  can  be  utilized  so  as  to 
serve  as  natural  barriers.  On  the  Simmer  &  Jack,  every  advantage  is 
taken  of  these  natural  barriers,  and  areas  requiring  filling  are  often  con- 
siderably extended  so  as  to  permit  of  their  use.  It  sometimes  happens 
that  immediate  use  cannot  be  made  of  such  a  barrier,  owing  to  the  fact 
that  all  the  ore  has  not  yet  been  removed  from  the  area  ultimately  to  be 
filled.  In  a  case  of  this  kind,  where  there  is  urgent  necessity  for  filling  a 
portion  of  the  area,  a  temporary  barrier  of  cheap  construction  may  be 
erected,  enabling  filling  operations  to  be  carried  on  immediately. 

The  number  of  openings  due  to  previous  mining  operations  through 
these  natural  barriers  is  not  usually  great,  enabling  large  areas  to  be 
completely  closed  at  comparatively  little  cost.  For  some  time  the  general 
practice  on  the  Simmer  &  Jack  has  been  to  close  up  the  drift  or  other 
openings  with  a  masonry  wall  provided  with  drainage  pipes.  More 
recently  such  drainage  has  been  effected  through  a  bed  of  sifted  clinker 
resting  on  a  perforated  platform.  It  has  been  suggested  that  in  order 
to  make  this  drainage  still  more  efficient  and  permanent,  a  system  might 
be  adopted  consisting  in  starting  a  drain  with  coarse  material,  such  as  rock 
9  in.  in  diameter,  and  gradually  working  up  with  rock  of  diminishing  size 
and  finally  with  clinkered  ash  until  the  fineness  of  the  material  to  be 
drained  has  been  reached,  Fig.  184.  This  system  has  everything  to  com- 
mend it  in  the  way  of  economy  of  construction,  permanency  and  efficient 
drainage.  The  drainage  just  described  is  supplementary  to  the  main 
drainage,  which  is  effected  by  means  of  drainage  launders.  The  drainage 
launders  originally  constructed  were  of  wood  or  iron  framing,  square  in 
section,  covered  with  cocoanut-fiber  matting.  These  were  found  to  be 
not  only  expensive  but  liable  to  collapse,  owing  to  the  perishable  nature 
of  the  matting.  The  greater  portion  of  the  sand  has  been  drained  through 
ordinary  square-section  box  launders  perforated  with  holes.  These 
launders  are  cheaply  constructed,  but  have  two  disadvantages.  They 
require  constant  attention  in  order  to  prevent  clogging  up  by  sand  before 
the  plugging  can  be  accomplished  and  they  are  liable  to  collapse,  although, 
of  course,  not  to  so  great  an  extent  as  the  cocoanut-fiber  matting  launders. 


244 


DETAILS  OF  PRACTICAL  MINING 


STOPING  245 

It  is  now  proposed  to  employ  a  stouter  box-shaped  launder  of  smaller 
internal  area.  The  perforations  will  be  covered  with  cocoanut  matting 
placed  over  wire  meshing.  It  has  been  suggested  that  these  might  be 
further  strengthened  by  filling  with  a  core  of  sifted  clinker.  Where  the 
drainage  at  the  bottom  of  the  areas  is  particularly  good  and  the  filling 
material  clean  sand  free  from  slime,  it  is  possible  to  dispense  with  the 
drainage  launder. 

Little  change  in  the  form  of  the  filling  launder  has  been  made  on  the 
Simmer  &  Jack  since  sand-filling  was  first  started.  For  a  time  wooden 
pipes  were  employed,  as  they  recommended  themselves  both  on  the 
score  of  cheapness  and  the  facility  with  which  they  could  be  erected. 
The  use  of  these  has  since  been  given  up  and  the  launder  at  present 
used  is  stouter  than  originally  employed  and  wears  better.  It  is  also 
deeper  in  proportion  to  its  width  so  as  to  prevent  overflow  of  pulp. 
The  bottom  is  lined  with  hard  wood  and  the  corners  provided  with  hard- 
wood fillets,  which  can  be  renewed  when  worn.  In  future  the  hardwood 
lining  will  be  replaced  by  old  rubber  belting. 

Where  the  dip  of  the  workings  is  not  sufficient  to  carry  the  pulp 
freely  along  the  launders,  water  is  added  from  some  underground  source 
of  supply.  This  is  preferable  to  using  water  to  thin  the  pulp  at  the 
underflow  of  the  cones  or  mixing  box  situated  at  the  top  of  the  bore 
hole,  as  the  water  has  subsequently  to  be  pumped  to  the  surface. 

The  cost  of  filling  per  ton  of  sand  residue  lowered,  varies  considerably 
from  month  to  month,  owing  to  fluctuations  in  the  tonnage,  and  the 
expenditure  incurred  underground  in  providing  for  current  as  well  as 
future  requirements.  On  the  Simmer  &  Jack  Proprietary  mines  during 
a  period  of  nine  months,  from  October,  1912,  to  June,  1913,  inclusive, 
172,535  tons  of  sand  was  lowered,  an  average  of  19,171  tons  per  month 
at  a  cost  for  surface  operations  of  6.736  cts.  per  ton  and  for  underground, 
of  13.108  cts.,  a  total  of  19.844  cts.  These  average  costs  include  a  con- 
siderable amount  expended  on  preparatory  work  on  areas  where  a  large 
amount  of  filling  remains  to  be  done.  It  is  probable  that  the  monthly 
tonnage  lowered  will  be  increased  soon.  These  two  factors  should  ap- 
preciably decrease  the  cost  per  ton  of  sand  lowered  in  the  future. 

Bulkheads  for  Hydraulic  Filling  (Bull.  60,  U.  S.  Bureau  of  Mines). — 
In  the  anthracite  regions  of  Pennsylvania,  where  hydraulic  filling  for 
the  underground  workings  is  extensively  practised,  certain  types  of 
bulkheads  have  become  standard  for  confining  the  filling  to  its  proper 
resting  place.  The  design  of  these  will  vary  chiefly  with  the  steepness 
of  the  working,  that  is,  the  dip  of  the  coal  bed.  The  particular  functions 
of  such  a  bulkhead  are  to  retain  the  solid  material  and  permit  the  passage 
of  water.  Certain  rules  for  proportioning  the  various  dimensions  are  as 
follows : 


246 


DETAILS  OF  PRACTICAL  MINING 


The  haunch  distance  B,  Fig.  185,  should  be  one-half  the  width  of  the 
opening  for  flat  workings  or  workings  dipping  up  to  10°;  two-thirds  the 
width  of  the  opening  for  chute  workings,  those  dipping  between  10° 
and  25°;  and  the  same  for  pitch  workings,  those  dipping  more  than  25°. 
The  width  of  opening  is  designated  by  A  in  the  illustrations.  The 
props  should  have  a  diameter  in  inches  equal  to  their  length  in  feet  for 


MASONRY     0AM 


FRONT     ELEVATION 


FROMT     ELEVATION 

BULKHEAD   FOR  DIP  OF  2S°l)f» 

FIG.    185. TIMBER    AND    MASONRY    DAMS    TO    CATCH    FLUSHED  -FILLING. 


flat  workings,  one-half  greater  for  chute  workings,  and  three-quarters 

greater  for  pitch  workings.     The  spacing  of  the  props  across  the  opening 

^ 
is  determined  as  follows:  For  flat  workings,  S  =  jj]  for  chute  workings, 

2  A.  4  A 

S.  =  5-77;  for  pitch  workings,  S  =  ^r^y,  it  being  understood  that  A  =  the 
o  Jo.  in 

width  of  the  opening  in  feet,  H  =  the  height  of  the  opening  in  feet,  S 
=  the  distance  from  center  to  center  of  props  in  feet. 


STOPING  247 

For  flat  workings,  the  method  of  construction  is  shown  in  1.  The 
props  are  securely  wedged  at  the  top,  and  manure  or  dirt  is  firmly  packed 
around  the  bottom  after  the  bottom  plank  has  been  attached,  to  prevent 
leakage.  The  inside  of  the  line  of  props  is  lined  with  IJ^-in.  planks  or 
double  1-in.  planks,  the  bottom,  sides  and  tops  being  carefully  joined 
or  patched  by  short  pieces  of  board  nailed  to  the  main  boarding  and  the 
solid  coal  or  pillar.  "For  the  steeper  of  the  flat  workings,  a  hay,  straw, 
burlap  or  brattice-cloth  packing  is  used,  or  a  drainage  trough  is  inserted, 
as  shown,  the  object  of  either  method  being  to  avoid  excessive  hydraulic 
head. 

The  method  of  constructing  a  bulkhead  for  a  chute  working  is  shown 
in  2.  In  some  cases  buttress  props  are  advantageous.  Drainage  should 
be  effected  by  the  use  of  a  trough,  as  illustrated.  The  chief  advantage 
of  this  trough  method  is  the  fact  that  the  water  is  rendered  available  for 
use  again  in  the  shortest  possible  period  of  time.  Where  the  inclination 
of  the  work  is  18°  or  more,  manure,  straw  or  hay  is  placed  between  the 
two  courses  of  boards  as  a  screener,  and  in  many  places  a  dry  wall  is 
constructed  to  act  somewhat  as  a  filter. 

A  typical  bulkhead  for  a  pitch  working  is  shown  in  3.  The  spacing 
rule  in  such  cases  may  call  for  more  props  than  can  be  inserted  in  one 
row,  and  therefore  a  second  row  becomes  necessary.  The  V-form  shown 
in  3  is  one  intended  to  resist  the  highest  pressures.  The  construction 
shown  in  2  is  also  applicable,  using  horizontal  timbers  hitched  into  the 
side  of  the  working  for  reinforcing  purposes.  Where  the  V-form  is  used, 
a  layer  of  fine  manure  and  dirt  is  placed  as  a  bedding  for  the  first  layer 
of  timbers  in  the  bottom  hitches.  The  planking  is  placed  vertical, 
with  as  few  nails  as  possible.  In  4  is  shown  an  alternative  method  of 
arranging  the  timbers.  The  use  of  a  screener  and  a  dry- wall  filter  is 
important  with  pitch  workings. 

Masonry  is  frequently  desirable  instead  of  timber,  the  most  common 
form  of  bulkhead  being  that  of  a  full-struck  arch,  with  radius  equal  to 
the  width  of  the  opening,  the  thickness  of  the  bulkhead  at  the  haunches 
being  equal  to  one-third  of  the  height,  and  the  crown  equal  to  one-sixth 
of  the  height.  These  conditions  are  illustrated  in  5.  Dry  walls  are  also 
used  for  bulkheads,  and  offer  the  advantage  of  being  both  a  filter  and  a 
retaining  wall  at  the  same  time.  Concrete  bulkheads  have  been  tried 
and  found  advantageous  where  great  pressures  are  encountered  and 
timber  is  expensive. 

Conveyor  Belts  for  Distributing  Filling  (Proc.,  Australasian  Institute 
of  Mining  Engineers). — The  North  mine  at  Broken  Hill  was  already 
partly  developed  on  the  800-ft.  level  when  the  present  management 
faced  the  problem  of  providing  an  efficient  distributing  system  for  filling. 
Above  that  level  reserves  did  not  warrant  the  heavy  cost  of  installing 


248 


DETAILS  OF  PRACTICAL  MINING 


a  system  to  fit  in  with  the  mine  lay-out  then  existing.     The  distribution 
of  filling  is  here  still  effected  by  means  of  tramming. 

The  filling  consists  of  residues  from  the  concentrating  mill.  The  main 
channels  for  its  gravity  run  consist  of  three  chutes.  These  are  carried 
down  outside  the  limits  of  the  orebodies,  and  the  filling  is  conveyed  from 
them  on  the  different  levels  to  the  various  winzes  in  the  orebodies  them- 
selves. A  complete  distribution  of  the  filling  is  made  to  every  winze 
on  each  successive  level,  the  practice  of  passing  filling  from  level  to  level 
through  working  stopes  being  in  no  place  adopted.  The  advantages  of 
this  are  many,  the  chief  being  that  in  no  place  are  stoping  operations 
hindered  on  account  of  filling  operations,  and  vice  versa. 


"^O^z  ~"-"-~^^^fciY/-.f£bi'          3-17  Chute  $»IH7Chut* 

/H&fcr***  I  I- 12  Winze 
9-IOChute  Wll-IIChute 
IIOO'FI  LEVEL 
FIG.    186. — PLANS  OF  BELT  DISTRIBUTION  ON  THE  LEVELS. 

Of  the  three  chutes,  the  central  extends  from  the  surface  to  the  800- 
ft.  level,  and  is  continued  below  that  level  only  in  the  form  of  a  winze 
which  enters  the  orebody  a  short  distance  below  the  level;  the  filling  is 
passed  into  the  stopes  off  this  winze  by  a  direct  gravity  run  from  the 
surface.  This  chute  is  situated  in  the  hanging  wall  of  the  lode,  but  down 
to  the  800-ft.  level  is  opposite  a  barren  zone  between  the  two  orebodies 
being  worked.  The  northern  limit  of  the  southern  of  the  two  orebodies 
lies  just  opposite  this  chute  on  the  800-ft.  level,  and  to  carry  the  chute 
down  in  the  hanging  might  lead  to  a  serious  interruption  of  filling  opera- 
tions should  any  movement  occur  in  the  hanging  wall. 

A  transfer  is  made  on  this  level  to  the  two  other  chutes  situated  350 
ft.  and  1000  ft.  respectively  north  of  the  first  chute.  Of  these  the  first, 


STOPING 


249 


8-10,  Figs.  186  and  187,  is  carried  from  the  hanging  wall  side  of  the  lode 
on  the  800-ft.  level  through  the  barren  zone  referred  to,  into  foot-wall 
country  at  the  1100-ft.  level,  and  below  that  level  will  continue  in  this 
safe  quarter.  The  second,  8-17,  is  entirely  in  foot-wall  country  below 
the  800-ft.  level.  This  transfer  of  the  main  chutes  into  foot-wall  country 
places  the  filling  operations  in  a  thoroughly  safe  condition. 


-6-nChute 


IZ50 


Southern  Orebody          ll-IJ Chute  Northern  OfeSody 

FIG.    187. — LONGITUDINAL  SECTION  OF  DISTRIBUTION  SYSTEM. 
) 

The  transfer  of  the  filling  from  the  central  chute  to  8-10  chute  is 
effected  by  means  of  8-2  belt,  from  which  filling  is  also  removed  into  8-7 
winze  in  passing.  The  delivery  end  of  this  belt  is  raised  so  as  to  deliver 
on  to  8-3  belt,  which  transfers  the  filling  materials  through  the  barren 
zone  in  the  lode-channel  to  8-4  belt.  A  temporary  chute  from  which 
filling  was  trammed  for  some  time  was  installed  at  this  transfer  station. 


FIG.    188. CROSS-SECTION    THROUGH     11-11     CHUTE,     SHOWING    SEPARATION     OF    BELT 

AND  TRAMMING  SYSTEMS. 

The  crosscut  containing  8-3  belt  is  carried  over  the  tramming  levels,  thus 
keeping  the  two  operations  quite  clear  of  each  other.  The  8-3  belt 
delivers  to  8-4  belt,  which  in  turn  delivers  into  8-17  chute.  Short  sub- 
sidiary belts,  8-5,  8-6  and  8-7,  take  the  filling  material  from  8-4  belt  at 
different  points,  each  delivering  into  a  separate  winze  in  the  orebody. 
From  the  chute,  8-1  belt  delivers  into  two  winzes  to  the  south. 

On  the  950-ft.  and  1100-ft.  levels,  the  plan  followed  is  essentially  the 


250  DETAILS  OF  PRACTICAL  MINING 

same  as  shown  in  the  illustrations.  A  cross-section  through  the  1100- ft. 
level,  Fig.  188,  showing  11-1  belt,  illustrates  the  typical  arrangement  of 
transfer  from  the  foot-wall  into  the  orebody,  and  the  manner  of  keeping 
clear  of  ore-tramming  operations. 

The  belts  are  motor-driven,  with  a  reduction  belt  drive  to  a  counter- 
shaft and  a  further  reduction  to  suitable  speed  of  driving  pulley  by  gear- 
ing. The  width  of  the  belt  used  is  18  in.  The  belts  are  run  on  day  shift 
only,  sufficient  filling  being  delivered  where  required  to  last  through  the 
following  two  shifts.  Colored  lights  with  switches  at  intervals  are  pro- 
vided as  a  means  of  signalling  to  the  feed  attendant  in  the  event  of  a  change 
of  feed  being  required.  Filling  is  removed  at  intermediate  winzes  by 
means  of  rubber  scrapers  set  diagonally  across  the  belt,  two  being  used 
at  each  winze ;  the  first  removing  the  bulk  of  the  filling,  while  the  second 
cleans  the  belt.  When  possible,  the  latter  is  not  used  and  the  belt  is 
allowed  to  deliver  a  small  amount  into  the  end  winze,  thus  reducing  the 
wear  on  the  belt. 

VARIOUS  DEVICES 

Sconces  for  Holding  Candles. — While  acetylene  is  used  in  some  mines 
and  grease  lamps  in  others,  there  are  many  in  which  candles  are  used  and 
will  be  for  some  time.  Mine  fires  can  frequently  be  traced  to  a  candle 
source.  It  is  not  the  candle  that  the  miner  is  using  himself,  but  the 
auxiliary  lights  at  some  chute,  turn  or  bad  place  in  the  run  from  the  ore 
pile  to  the  chute  that  cause  mine  fires.  The  miner  takes  home  his  candle- 
stick but  frequently  forgets  to  put  out  the  auxiliary  lights.  He  can- 
not be  expected  to  provide  candlesticks  for  these,  and  furthermore,  a 
candlestick  is  little  safer  than  the  two  nails  driven  into  a  timber,  which 
are  usually  used.  The  proper  method  of  holding  these  auxiliary  lights 
is  in  a  sconce,  an  old  Cornish  device.  As  the  name  implies,  it  is  simply 
a  candle  holder,  fastened  to  the  side  of  an  upright  timber.  To  receive 
the  candle,  it  should  have  a  holder  or  socket,  preferably  split  so  that  the 
miner  can  easily  dig  out  any  old  snuff;  it  should  have  a  back  to  protect 
the  timber  from  the  flame;  and  it  is  also  well  for  the  bottom  to  have  a 
raised  lip  to  catch  the  drippings.  The  candle  cannot  drop  out  as  it 
burns  down,  and  so  fall  to  the  floor.  The  bottom  plate  catches  the 
drippings  and  prevents  a  large  accumulation. 

A  sconce  used  in  the  mines  of  the  Copper  Queen  company  at  Bisbee, 
Ariz.,  is  shown  in  Fig.  189.  This  is  a  cast-iron  affair  made  heavy  to  resist 
rough  usage.  The  socket  is  cast  split,  and  the  hole  for  hanging  on  the 
nail  is  made  like  a  key-hole  with  the  large  part  down,  so  that  the  sconce 
cannot  easily  be  knocked  off.  These  cast-iron  sconces,  however,  must  be 
made  at  a  foundry;  they  are  also  broken  frequently  at  the  nail  hole. 
The  lighter  sheet-metal  sconces  are  preferable  as  being  less  liable  to 


STOPING 


251. 


break  and  capable  of  being  made  at  any  blacksmith  shop  at  odd  times 
out  of  scrap  plate.  A  good  type  of  sheet-metal  sconce  is  that  illustrated 
in  Fig.  190,  used  at  the  Highland  Boy  mine  at  Bingham,  Utah.  This  is 
equipped  with  a  handle  at  the  top  for  carrying  purposes.  The  sheet- 
iron  frame  of  the  sconce  bends  out  at  the  bottom  to  catch  the  drippings, 
while  at  the  top  it  is  flared  to  keep  the  flame  from  reaching  a  cap  when 
the  sconce  is  hung  high  on  the  post.  The  candle  is  held  in  a  socket  riveted 
to  the  frame,  the  bottom  of  the  socket  being  closed  so  that  a  snuff  can- 
not fall  through. 


PIG.        189. FIG.    190. HIGH-  FIG.    191. CLEVELAND- 

COPPER      QUEEN      LAND    BOY     SHEET-      CLIFFS     SHEET-IRON 
CAST  SCONCE.  METAL  SCONCE.  SCONCE. 

A  simpler  sconce  is  that  shown  in  Fig.  191,  devised  by  Captain  Collick 
of  the  Cleveland-Cliffs  Iron  Co.'s  Lake  mine  at  Ishpeming,  Mich.  It 
is  a  piece  of  sheet  iron  with  one  end  sharpened  to  stick  into  the  timber 
and  the  other  turned  up  and  bent  into  a  socket  about  an  inch  high  to 
hold  the  candle.  Since  it  is  8  or  9  in.  long,  the  timber  is  safe  from  the 
flame  but  the  drippings  are  allowed  to  fall  to  the  floor.  A  still  cheaper 
sconce  can  be  made  from  an  old  lard  pail.  The  sheet  forming  the  sides 
of  the  pail  is  flattened  and  the  bottom  is  bent  up.  The  device  is  held 


FIG.  192. HAROLD  SCONCE  CONSISTING  OF  SAUCER,  STICK  AND  SOCKET. 

to  the  timber  by  two  heavy  nails  that  also  serve  to  hold  the  candle.  Drip- 
pings and  the  snuff  if  it  should  fall  out  are  caught  by  the  trough-shaped 
flattened  piece.  In  Fig.  192  is  shown  a  candle-sconce  used  in  the  Harold 
mine  on  the  Mesabi.  It  is  of  an  unusually  substantial  pattern,  both 
saucer  and  stick  being  worked  out  by  the  blacksmith.  The  stick  can 
be  driven  into  a  post  securely  by  a  rap  on  the  end,  this  being  protected 
by  bending  over  it  a  lug  of  the  saucer.  The  saucer  itself  catches  all 
drippings. 


252  DETAILS  OF  PRACTICAL  MINING 

Ore  Chutes  of  Sheet  Steel  (Proc.,  Australasian  Institute  of  Mining 
Engineers). — Circular  steel  ore  chutes  have  been  used  on  the  South  Blocks 
mine  for  several  years,  and  continue  to  give  satisfaction  under  the 
conditions  existing  there.  The  ones  first  installed  were  16  in.  in  diameter 
and  %e  m-  thick,  being  rolled  from  4  X  4-ft.  plates.  The  vertical  joint 
was  made  by  riveting  a  cover  plate  on  the  outside,  and  the  lugs  for 
fastening  one  length  to  the  one  below  were  also  riveted.  As  these  proved 
too  small,  some  of  20-in.  diameter,  rolled  from  5  X  4-ft.  plate  were  tried, 
but  developed  the  same  fault.  Next,  some  30-in.  diameter  by  J^-in. 
were  tried,  made  from  8  X  4-ft.  plates,  and  similar  in  construction  to 
the  others.  The  size  of  the  latter  proved  adequate,  but  the  riveting 
was  a  source  of  weakness,  as  the  heads  of  the  rivets  got  worn  off,  partly 
by  abrasion,  but  mainly  by  the  constant  jarring  of  the  falling  ore.  This 
loss  of  rivets,  in  the  case  of  the  longitudinal  joints,  caused  the  tube  to 
bulge  and  the  chute  to  hang  up.  In  case  the  lugs  became  detached,  the 
tube  to  which  they  belonged  slipped  down  and  left  an  annular  space, 
in  which  the  ore  again  collected  and  hung  the  pass  up.  To  overcome 
this  defect  the  present  type  of  tube  was  adopted,  with  no  rivets  at  all  in 
the  lugs,  and  with  those  in  the  longitudinal  seams  placed  far  enough 
back  from  the  side  of  the  chute  to  allow  of  the  jarring  effect  being 
deadened. 

The  sections  are  made  by  cutting  slots  in  4  X  8-ft.  plates  with  a 
^-in.  slotting  punch,  the  final  cut  in  every  case  being  made  with  a 
round  instead  of  a  rectangular  punch,  thus  giving  a  round  root  to  the 
lugs,  to  prevent  tearing.  The  circular  holes  for  riveting,  and  for  attach- 
ing the  slings,  are  punched  at  the  same  time  and  by  the  same  machine. 
Provision  is  made  for  three  lugs  on  each  longitudinal  and  on  each  cir- 
cumferential seam,  the  bottom  longitudinal  lug  also  serving  as  an 
additional  circumferential  support.  After  cutting,  the  plates  are  bent 
uniformly  in  the  rolls  until  the  opposite  edges  about  touch.  The  lugs  are 
next  bent  cold  by  hand,  using  a  dog,  shown  in  the  bottom  left  corner 
of  Fig.  193,  consisting  of  a  3-in.  head,  having  a  slot  in  it  4  in.  deep  by 
]/2  in.  wide,  and  provided  with  a  stout  iron  handle.  The  lugs  of  the 
longitudinal  seams  are  bent  out  square  in  one  operation,  but  those  for 
the  annular  joints  are  first  bent  out  square  to  the  axis  of  the  tube;  then 
the  hold  of  the  dog  is  shortened,  and  they  are  bent  back  parallel  to 
the  axis.  The  edges  of  the  longitudinal  seams  are  then  pulled  up  to- 
gether and  riveted. 

The  first  section  for  each  chute,  or  the  "starter,"  as  it  is  called,  has 
the  same  longitudinal  joint,  but  the  lugs  are  replaced  by  4  X  4  X  M~ 
in.  angle-iron  feet,  which  rest  on  the  chute  timbers  and  form  the  foun- 
dation for  the  chute.  Riveting  is  again  avoided  by  attaching  the  feet 
in  the  following  manner :  Three  pairs  of  circumferential  slots  are  punched 


STOPING 


253 


,- — ,,  -_..>*    p— 


A$£*iH 


254  DETAILS  OF  PRACTICAL  MINING 


X  K  in->  with  2-in.  centers;  the  1^-in.  metal  left  between  is  then 
sheared  in  the  center,  and  the  two  pieces  of  metal  forced  back  to  make 
two  1%  X  IJ^-in.  lugs.  Over  these  is  placed  a  5-in.  length  of  4  X  4  X 
J^-in.  angle,  slotted  to  fit  the  lugs,  and  these  lugs  are  then  hammered 
back  to  grip  the  angle  iron.  Half  and  three-quarter  sections  are  also 
used,  being  made  from  2  X  8-ft.  and  3  X  8-ft.  plates,  the  object  being 
to  suit  the  height  of  the  filling  in  the  stope.  The  end  dimensions  of 
these  short  sections  are  the  same  as  the  ordinary  ones,  but  the  central 
longitudinal  lug  has  to  be  dispensed  with  from  lack  of  room  on  the 
plate.  The  different  lengths  of  the  slots  and  lugs  on  the  top  and  bottom 
circumferential  seams,  give  the  required  taper  to  each  section.  The 
top  of  each  section  has  a  minimum  inside  diameter  of  2  ft.  5  in.,  and 
the  bottom  a  maximum  outside  diameter  of  2  ft.  4J^  in.,  to  allow  of 
fitting  together.  Three  thicknesses  of  plate  are  used,  %  in.  for  the  first 
60  ft.  above  the  level,  ^{Q  in.  from  the  60-ft.  to  the  110-ft.  point,  and 
J/£  in.  for  the  remainder;  the  cost,  complete,  of  each  section,  from  4X8- 
ft.  plate,  is,  respectively,  $19.20,  $18  and'  $15.60. 

In  starting  from  the  level,  two  10  X  10-in.  Oregon  pine  foundation 
pieces  of  a  length  to  suit  the  conditions  are  first  put  in,  Fig.  194,  resting 
on  a  2-in.  projection  of  the  caps  of  the  level  sets,  an  additional  hold  some- 
times being  given  by  spiking  a  4  X  10-in.  piece  vertically  to  the  lugs. 
Two  pieces  7  ft.  by  10  X  10  in.  are  next  placed  transversely  to  these  and 
blocked  2  ft.  5  in.  apart,  and  then  two  5-ft.  pieces  parallel  to  the  founda- 
tion pieces,  similarly  blocked  2  ft.  5  in.  apart.  The  starting  section  is 
fitted  between  these,  the  lugs  resting  on  the  top  of  them,  and  the  whole  is 
made  rigid  by  packing  with  filling.  The  chutes  are  placed  30  ft.  apart 
along  the  level  and  in  some  cases  have  been  taken  up  140  ft.  above  the  back 
of  the  drift  in  stopes  averaging  30  ft.  wide,  representing  about  15,000 
tons  handled  per  chute  without  any  renewals  or  repairs.  Some  of  the 
chutes  have  been  lost,  but  most  of  these  were  16  and  20  in.  in  size,  the 
rest  being  ruined  by  firing  with  gelignite  when  clogged.  Repairs  are 
difficult,  but  provided  care  is  taken  to  avoid  sharp  bends,  which  allow  the 
ore  to  pound  out  the  under  side  of  the  bend,  and  no  firing  of  clogged  chutes 
is  permitted,  no  repairs  are  necessary  where  the  chutes  are  properly 
spaced.  The  advantages  of  these  chutes  are:  (1)  Their  moderate  first 
cost  and  great  wearing  qualities  which  eliminate  renewals  and  repairs; 
(2)  the  small  size  they  can  be  made  without  an  undue  tendency  to  clog, 
lessening  the  chance  of  accident  by  falling  into  them;  (3)  their  adaptability 
to  stoping  conditions,  as  no  special  care  is  needed  when  firing  ground  on 
top  of  them;  (4)  their  impervious  nature,  which  prevents  any  extremely 
rich  ore  from  being  lost,  and  also  confines  sand  filling  to  the  stope,  a 
matter  of  great  difficulty  in  wet  mines;  and  (5)  the  ease  and  cheapness  of 
installing  each  section,  as  each  tube  is  made  to  fit  the  one  below.  Results 


STOPING  255 

on  the  South  Blocks  mine  show  that  for  the  conditions  existing  there,  the 
steel  chute  can  do  its  work  quite  as  well  as  any  form  of  timber  chute, 
and  the  question  of  its  adoption  depends  directly  on  the  relative  prices 
of  steel  and  timber. 

Chute  Conveyor. — A  convenient  form  of  shaking  chute  is  shown  in 
Fig.  195.  The  chains  to  the  end  bands  are  conveniently  attached  to 
eye-bolts  in  the  hanging  wall.  At  the  end  a  hole  is  provided  in  the 
bottom  for  a  bolt  to  connect  successive  sections.  The  number  of  sections 


4"Boi!erP/afe 
2l"x96' 


for  Bo/ 1 

FIG.    195. SHAKING  CHUTE  FOR  USE  IN  FLAT  STOPE. 

is  limited  by  the  weight  which  can  be  easily  swung.  The  troughs  are 
made  of  ^-in.  boiler  plate,  two  being  obtained  from  each  standard  sheet, 
42  X  96  in.  The  straps  binding  the  ends  are  J£  X  1^  X  26  in.,  the 
chains  are  of  ^-in.  material.  The  action  of  the  chutes  is  obvious.  A 
line  of  them  is  hung  from  the  car  or  bin  to  the  shoveling  point  near  the 
face  and  as  muck  is  shoveled  into  them,  they  are  swung  in  the  direction 
of  their  long  axis  and  the  material  is  conveyed  by  bumping  to  the  lower 
end.  In  case  it  is  possible  for  the  muck  to  slide  without  bumping,  the 
troughs  can  be  laid  on  the  foot-wall,  in  a  zigzag  fashion  if  desired,  so  as 
to  reach  the  shoveling  point  in  the  most  convenient  manner. 


VII 
TIMBER  STRUCTURES 

Bins — Chutes  and  Gates — Skip  Pockets — Headframes — Turn  Sheaves — 
Trestles — Ginpoles — Various  Devices 

BINS 

Improved  Type  of  Ore  Bin  (By  Wilbur  E.  Sanders). — In  mining  and 
metallurgical  operations,  bins  are  employed  for  purposes  of  collection  and 
of  distribution,  as  receptacles  within  which  materials  may  be  collected, 
wherein  reserve  materials  may  be  stored  and  from  which  such  reserves 
may  be  drawn  as  required.  The  important  functions  of  bins  may  there- 
fore be  summed  up  as  those  of  storage  and  the  delivery  of  materials. 
The  two  general  types  of  bins  are  the  flat  bottom  and  the  inclined  bottom. 

In  Fig.  196,  ABCD  represents  the  outline  of  a  flat-bottom  bin  in 
vertical  cross-section.  It  is  essentially  self-contained,  its  frame  being 
supported  directly  upon  the  solid  bed  or  sill  parts.  This  type  is  unques- 
tionably the  simplest  to  construct,  the  strongest  when  constructed,  and 
of  itself,  in  all  respects  save  that  of  immediate  delivery  at  the  chute, 
the  most  satisfactory,  being  per  ton  of  capacity  the  most  economically 
built,  reinforced  and  repaired.  When  filled,  the  upper  surface  of  the 
material  will  have  "coned"  to  approximately  the  outline  FGHI,  when  the 
entire  cubical  contents  of  the  bin  will  be  available  for  the  storage  of 
material.  Discharge  can  take  place  until  a  line  EC  is  reached,  coinciding 
with  the  angle  of  repose  of  the  material,  when  delivery  will  cease.  The 
material  in  the  space  EBCt  will  remain  in  place  within  the  bin  as  reserve 
or  stored  material.  From  the  surface  EC  delivered  material  will  be 
deflected  and  discharged  through  the  chute.  With  material  thus  rolling 
or  sliding  upon  similar  material  in  its  discharge  from  the  bin,  the  effects 
of  shock  and  abrasion  are  minimized.  The  slope  of  the  inclined  plane 
EC  will  vary  with  the  angle  of  repose  of  the  material  in  the  bin.  Fluent 
materials  will  flow  readily  at  a  relatively  low  angle,  while  others  will  dis- 
charge only  at  a  steeper  angle.  Material  of  a  clayey  wet  nature  may 
stick  so  that  only  excessive  weight  of  overlying  material  will  force  it  to 
discharge  and  even  the  bin  may  become  all  but  clogged. 

The  material  stored  as  reserve  within  the  triangular  space  EBC,  since 
it  can  be  shoveled  out,  is  available  for  use  in  the  mill  if  the  supply  to  the 

256 


TIMBER  STRUCTURES 


257 


o    . 


17 


258  DETAILS  OF  PRACTICAL  MINING 

bin  should  cease.  This  is  a  characteristic  of  the  flat-bottom  bin,  of  great 
importance  in  emergencies.  It  is  counterbalanced,  however,  by  the  fact 
that  when  such  a  reserve  is  once  shoveled  out,  it  must  be  replaced  before 
the  b'n  can  again  automatically  deliver  material. 

In  Fig.  197,  AECD  may  be  taken  to  represent  a  cross-section  of  an 
inclined-bottom  bin.  The  inclined-bottom  bin  is  fundamentally  less 
securely  foundationed  than  is  the  flat-bottom  structure;  is  essentially 
unstable,  in  that  it  represents  a  wedge  supported  on  edge.  Its  construc- 
tion presents  difficulties  that  can  be  overcome  only  -by  using  an  ample 
factor  of  safety.  Furthermore,  the  excessive  weight  of  superimposed 
material  tends  to  pack  that  within  the  wedged  portion  of  the  bin  so  hard 
that  it  presses  against  the  front  parts  of  the  structure  and  even  may 
spring  them  outward  and  force  them  from  position.  The  inclined  bot- 
tom is  also  subjected  to  excessive  wear  and  breakage  by  falling  material 
and  to  abrasion  by  the  sliding  of  the  material  during  its  discharge.  Re- 
pairs to  the  bottom  are  consequently  extensive  and  expensive.  The 
large  space,  represented  by  EEC  is  wasted,  where  otherwise  it  would  be 
available  for  a  reserve  of  material.  The  real  value  of  the  inclined-bottom 
bin  lies  in  its  facility  of  discharge,  whether  it  be  empty  or  full.  All 
material  that  is  contained  or  may  be  dumped,  is  available  for  immediate 
discharge  except  for  negligible  remnants  in  the  corners. 

By  the  application  of  a  simple  device,  the  favorable  characteristics 
of  both  types  of  bin  may  be  obtained  in  a  single  structure  with  the 
practical  elimination  of  their  unfavorable  characteristics.  In  Fig.  197 
is  shown  an  inclined  leaf,  shelf  or  platform,  JK,  within  the  bin,  approxi- 
mately coincident  with  or  at  a  slightly  steeper  inclination  than  the  angle 
of  repose  of  the  material  to  be  handled  and  placed  preferably  independent 
of  the  bottom,  front  and  rear  of  the  bin.  Its  lower  edge  is  far  enough 
above  the  bin  bottom  to  permit  material  beneath  and  behind  it  to  be 
shoveled  into  the  chute.  'Usually  the  leaf  alone  would  properly  deliver 
the  material,  but  under  some  conditions  it  might  become  advisable  to 
connect  it  with  the  chute  by  a  .false  or  removable  leaf;  this  false  leaf  may 
be  removed  whenever  it  is  necessary  to  shovel  out  the  stored  material. 
The  upper  edge  of  JK  extends  far  enough  to  catch  all  the  falling  material 
from  above.  If  the  bin  be  empty,  the  falling  material  will  flow  back 
beneath  the  lower  edge  of  the  leaf,  forming  a  pile  JCL,  over  the  front 
surface  of  which  any  added  material  will  slide  to  the  chute.  This  means 
almost  immediate  delivery  of  material  dumped  after  the  bin  has  been 
emptied.  If  the  chute  is  closed  and  dumping  is  continued,  the  material 
will  cone  up  on  the  floor  of  the  bin  and  on  the  leaf,  and  will  then  overflow 
the  upper  edge  of  the  leaf  so  as  to  fill  the  space  behind  and  below  it. 
There  is  thus  no  waste  space,  except  that  occupied  by  the  inclined  leaf 
and  its  supports, 


TIMBER  STRUCTURES 


259 


The  leaf  JK  can  be  readily  applied  to  any  flat-bottom  bin  already 
constructed.  Since  before  any  great  mass  of  material  rests  on  the  leaf, 
it  will  be  supported  by  that  which  has  been  forced  beneath  it,  it  is  evident 
that  it  will  not  have  to  support  any  extraordinary  weight  and  need  not 
be  of  extraordinary  strength.  It  must,  however,  be  so  constructed  as 
to  withstand  the  impact  of  falling  material  and  abrasive  action.  It 
may  be  constructed  as  an  integral  part  of  the  bin  structure  or  may  be 
made  removable;  it  may  extend  the  full  length  of  the  bin,  or  may  be  of 
a  length  only  sufficient  to  catch  the  dumped  material  and  direct  it  to 
the  chute. 

Fig.  198  exhibits  one  method  of  applying  the  leaf  to  a  timber  bin; 
simple  angle-frames  attached  to  the  sill-pieces  by  lag-screws  support  the 
device.  To  these  frames,  spaced  at  proper  intervals,  the  flooring  of  the 
leaf  is  attached,  and  this  flooring  is  sheathed  either  with  sheet  steel,  or 


FIG.    199. CROSS-SECTION    OP  BIN    WITH    NEW    TYPE    OF   BOTTOM. 

with  railroad  rails.  The  surfacing  is  bolted  to  the  timber  floor  of  the  leaf, 
secured  by  nuts  and  locknuts  applied  from  beneath.  Thus  the  leaf 
may  be  repaired  with  little  difficulty,  since  all  parts  are  accessible. 
Furthermore  the  wearing  parts  are  of  relatively  small  size  and  therefore 
the  expense  of  making  repairs  is  reduced  to  a  minimum. 

Bin  with  Compromise  Bottom. — A  campaign  of  reconstruction  put 
through  in  1914  by  the  Ellamar  Mining  Co.,  of  Alaska,  involved  the  build- 
ing of  a  new  bin  at  the  mine,  with  a  capacity  of  1200  tons  of  copper  ore. 
Among  the  main  features  of  this  bin  are  its  division  into  three  compart- 
ments each  holding  400  tons,  the  placing  of  all  tie  rods  in  the  partitions 
so  as  to  protect  them  from  falling  ore  and  particularly  the  means  adopted 
to  overcome  the  disadvantages  of  both  the  inclined  and  the  flat  bottom. 
For  this  last  purpose  a  housing  was  built  in  the  lower  rear  corner  of  the 


260 


DETAILS  OF  PRACTICAL  MINING 


U 20L0'- - 


FIG.    200. — PLAN   AND   SECTION   OF   ROUND-TIMBER  BIN. 


TIMBER  STRUCTURES 


261 


structure,  as  shown  in  the  cross-section,  Fig.  199.  The  space  rilled  by 
this  reduces  by  so  much  the  quantity  of  ore  tied  up  and  unavailable,  a 
point  of  importance  when  the  ore  is  of  high  grade,  while  it  provides 
space  for  storage  when  desired;  at  the  same  time  the  difficult  and  expen- 
sive construction  of  the  sloping  bottom  bin  is  avoided. 

A  700-ton  Ore  Bin  of  Logs  (By  W.  L.  Kidston) .— The  ore  bin 
illustrated  in  Fig.  200  was  built  by  W.  A.  Dickey,  at  the  Threeman  mine 
on  Landlock  Bay,  Alaska,  about  5  years  ago,  and  besides  being  cheap 
for  its  size,  has  shown  its  stability  by  withstanding  a  heavy  earthquake 
shock  and  showing  no  sign  of  strain,  although  at  the  time  of  the  shock 


t4- 

1- 

-H= 

T 

,   4H.iillliSi 

T 

tl1 

r 

5ide  Elevation 

Sectional  Elevati 

FIG.    201. PLAN    AND    ELEVATIONS    OF    CENTER-DISCHARGE   BIN. 

one  side  was  full  of  ore  and  the  other  about  empty.  The  bin  is  built  of 
12-  to  16-in.  logs,  24  ft.  and  46  ft.  long.  The  large  logs  cost  $1.50  each, 
delivered,  and  the  smaller  ones  in  proportion.  The  logs  are  notched 
down  just  as  for  a  log  house  and  are  chinked  with  cord- wood  sticks  at  $3 
per  cord;  labor  cost  $3.50  per  day  and  the  total  cost  of  the  bin  was  $800. 
Its  capacity  is  700  tons.  The  bin  is  divided  in  the  center  by  a  course  of 
logs  similar  to  the  ends  and  notcned  to  prevent  spreading  from  interior 
pressure.  The  sloped  sides  near  the  bottom  are  planked  with  3  X  12- 
in.  lumber.  The  roof  is  of  shakes.  Finger  chutes  of  the  Treadwell 
pattern,  not  shown  in  the  sketches,  are  used  on  the  eight  discharge 
openings;  the  latter  are  staggered  on  opposite  sides  of  the  center  so  that 


262  DETAILS  OF  PRACTICAL  MINING 

no  two  are  exactly  opposite.  The  ore  comes  from  the  mine,  a  distance 
of  300  ft.,  and  is  dumped  into  the  top  of  the  bin  from  the  mine  cars. 
From  the  bottom  the  ore  is  carried  to  the  ship  at  the  dock  600  ft.  distant. 
Seven  men  load  60  tons  per  hour.  The  pitch  of  the  roof  is  steep  in  order 
that  the  snow  may  slide  off. 

Round -timber  Bin  with  Novel  Emptying  System  (By  E.  S.  Shaw). — 
A  bin  on  the  dumps  of  Stratton's  Independence,  Ltd.,  in  the  Cripple 
Creek  district  has  for  foundations  two  long  cribs  built  10  ft.  apart  on 
the  surface  of  the  loose  rock  and  filled  with  waste  rock,  Fig.  201.  Waste 
from  the  mine  is  dumped  around  the  sides  of  the  bin  to  insure  greater 
stability.  The  bin  timber  is  chiefly  8-in.  round,  with  the  crevices  around 
the  sides  filled  with  3-in.  and  4-in.  round  pieces.  The  stringers  are  of 
10-in.  square  material  and  the  flooring  of  3-in.  planks. 

The  method  of  emptying  the  bin  is  its  novel  feature.  The  car 
to  be  filled  is  run  under  the  first  planks  that  are  covered  with  ore.  The 
loader  stands  on  the  platform  outside  of  the  bin  so  as  to  be  safe  from  fall- 
ing rock  and  loosens  the  first  plank,  pulling  it  ahead  with  his  pick. 
By  doing  this  with  each  plank  in  turn  until  he  reaches  the  ore,  he  has 
a  space  sufficiently  large  to  allow  it  gradually  to  fill  his  car.  The  ore 
will  run  until  the  sloping  face  reaches  an  angle  of  about  45°,  the  angle  of 
repose  of  loose  rock.  The  loosening  of  more  planks  provides  a  greater 
quantity  of  material.  The  capacity  of  the  bin  is  220  tons.  The  entire 
costs  of  construction  were,  for  labor,  $245;  for  material,  $269. 

CHUTES  AND  GATES 

Development  of  Chute  and  Gate  (By  Albert  E.  Hall). — The  chutes 
here  illustrated  were  tried  out  at  Creighton  Mine,  Ont.,  where  the  ore  is 
a  mixture  of  pyrrhotite  and  chalcopyrite  with  a  little  pentlandite,  and  is 
consequently  heavy  material  to  handle.  Besides  being  heavy,  the  ore 
comes  to  the  chutes  in  large  pieces  because  the  ground  has  many  slips 
in  certain  sections  and  because  of  the  presence  of  a  large  amount  of  rock 
from  a  caved  section  of  the  mine.  These  large  pieces  often  have  to  be 
blasted  in  the  chutes,  so  that  the  latter  have  to  stand  hard  usage  both 
from  the  hammering  of  the  ore  and  from  blasting. 

Mining  at  Creighton  is  carried  on  by  the  shrinkage  method.  The 
ordinary  system  of  developing  a  level  has  been  changed,  however.  On 
the  older  levels  drywalls  were  used,  while  on  the  new  levels  rock  drifts 
replace  the  drywalls.  In  the  drywall  method  when  the  point  is  reached 
where  the  chute  is  desired,  the  wall  is  stopped  and  the  chute  built  and 
then  the  masons  start  the  wall  on  the  other  side  of  the  chute.  In  the 
rock-drift  method  a  raise  is  put  up  to  a  height  of  from  8  to  10  ft.  and 
the  chute  built  under  this.  These  raises  are  known  as  box-holes,  and 
the  stope  is  started  from  the  top  of  them. 


TIMBER  STRUCTURES 


263 


The  first  chute  considered  in  this  method  was  the  Lawson,  which 
had  an  underswung  arc  gate,  with  the  concave  side  of  the  arc  toward 
the  muck.  Its  general  design  is  shown  in  Fig.  202.  The  construction 
of  the  chute  itself  was  similar  to  the  Henrotin  chute  shown  in  Fig.  207, 
the  only  difference  being  that  the  pieces  marked  A  were  made  longer  in 
the  Lawson  chute  to  support  the  lip.  The  gate  was  operated  by  an  air- 
lift suspended  from  above  and  controlled  by  means  of  a  three-way  valve. 


L,2*Z*4( 


FIG.    202. LAWSON 

CHUTE. 


FIG.    203. FIRST 

KEATING    GATE. 


FIG.  204.— 
COUNTERBALANCED 
UNDERSWUNG  GATE. 


It  frequently  happened  that  small  pieces  would  get  between  the  gate  and 
the  lip  or  between  the  gate  arms  and  the  lip,  thus  making  it  either  hard 
to  open  the  gate  or  harder  to  close  it,  the  latter  causing  a  spill  in  the 
drift  which  took  a  long  time  to  clean  up.  A  remedy  was  therefore  sought, 
and  the  result  was  the  Henrotin  chute.  The  gate  of  the  Henrotin  chute 
instead  of  having  the  concave  side  of  the  arc  toward  the  muck  had  the 
convex  side  toward  it  but  was  also  underswung.  No  lip  was  needed 


Counterweight 
-•zttHb.  Rails 


^Bearing 
\4~Frcime 


FRONT  ELEVATION 


SIDE 
ELEVATION 


FIG.    205. MINNESOTA    GATE.  FIG.    206. FINGER    CHUTE. 


on  the  chute  because  the  gate  was  supported  in  the  side  plates,  and  the 
front  of  the  gate  became  the  bottom  of  the  chute  when  it  was  opened. 
The  air  lift  was  placed  below  the  chute.  Putting  the  convex  side  of  the 
gate  toward  the  ore  relieved  the  pressure  against  it  and  thus  made  it 
easier  to  operate  and  control.  The  arc  of  the  gate  must  be  a  part  of  a 
circle  or  it  will  not  operate,  and  one  of  the  difficulties  was  to  get  it  made  true 
to  radius.  Trouble  similar  to  that  experienced  with  the  Lawson  chute 


264 


DETAILS  OF  PRACTICAL  MINING 


was  encountered  with  this  one; '-fine  material  got  between  the  chute  and 
the  gate  and  interfered  with  its  operation ;  fine  material  also  went  through 
on  the  air-lift  below  and  sometimes  stopped  its  operation.  Both  chutes 
had  an  opening  too  small  for  the  size  of  muck  that  was  being  handled 
from  the  stope,  and  too  much  blasting  was  necessary  near  the  gates, 
which  did  not  stand  up  under  the  heavy  duty.  This  made  the  cost  of 
repairs  high.  The  air-lifts  consumed  a  large  quantity  of  air,  making 
the  operating  cost  high  and  reducing  the  amount  of  air  available  for  the 
drills.  In  winter  there  was  trouble  with  the  air-lifts  because  of  freezing. 
These  facts  led  to  the  construction  of  a  chute  with  a  larger  opening  and 
without  a  mechanical  gate. 

A  chute  called  the  Keating,  Fig.  208,  was  then  tried.     This  was  a 
long  wide  box,  which  was  quickly  built  and  required  comparatively 


u. 10'- 

/ 


FRONT  ELEVATION  SIDE  ELEVATION 

FIG.  207. THE  HENROTIN  CHUTE. 

little  timber.  The  first  of  these  chutes  was  constructed  with  a  slope  of 
15°,  which  proved  too  flat;  but  one  of  25°  with  an  iron  plate  on  the  bottom 
was  satisfactory.  For  a  gate,  a  25-lb.  rail  was  fastened  to  each  post  and 
set  out  from  it,  as  shown  in  Fig.  203,  so  that  an  iron-bound  plank  could 
be  run  across  the  front  of  the  chute.  This  plank  was  hard  to  raise 
on  account  of  the  muck  behind  it  and  soon  became  badly  bent,  when  it 
was  impossible  to  move  it.  The  trammers  and  chute-men  replaced  the 
planks  with  long  drill  steel,  which  worked  well,  except  when  fine  material 
ran  in  the  chute;  then  there  would  be  spills  which  buried  the  car  and 
required  much  time  to  clear  up.  When  the  steel  replaced  the  planks, 
staples  were  used  in  place  of  the  rails.  To  overcome  the  difficulty  of  the 
fine  material  running  over  the  steel,  a  gate,  known  locally  as  the  Minne- 
sota gate,  was  tried  and  has  become  the  regular  gate  throughout  the 


TIMBER  STRUCTURES 


265 


mine.  It  is  so  satisfactory  that  it  leaves  little  to  be  desired.  As  shown 
in  Fig.  205,  two  25-lb.  rails  with  ends  8  to  10  in.  long,  bent  at  45°,  are 
spiked  to  the  chute  post  and  to  the  lagging  over  the  drift.  Across 
these  is  placed  round  timber,  which  can  be  raised  and  dropped  easily 
to  control  the  run  of  the  ore  from  the  chute.  The  timber  becomes  worn, 
but  can  be  replaced  with  no  trouble  when  the  chute  hangs  up  a  little. 

When  the  rock-drift  method  was  started  the  chutes  had  to  be  adapted 
to  the  box  holes.  At  first  a  long  flat  chute  was  tried,  which  was  a  cross 
between  a  chute  and  a  shoveling  platform.  It  had  low  sides  and  the 
raise  was  a  long  distance  in  from  the  chute.  The  chute-man  stood 
up  on  the  rock  at  the  side  and  reached  over  the  timber  to  pull  the  material 


g 

% 

W+....4'..-.. 
~m  ^BoilerPlate- 


-7'- 


y/////////. 

SIDE  ELEVATION 


FRONT  ELEVATION 


FIG.    208. THE    KEATING    CHUTE. 

down  into  the  car.  The  loading  was  slow  and  when  the  chute  blocked  it 
was  too  far  back  to  blast  it  down  quickly.  The  chute  was  then  made 
steeper  and  a  counterbalanced  gate  of  the  underswung  type,  shown  in 
Fig.  204,  was  tried.  The  gate  was  swung  in  two  bearings,  one  on  each 
post,  and  had  its  concave  side  toward  the  muck.  Two  angle-iron  arms, 
as  shown,  were  fastened  on  each  side  of  the  gate,  one  near  the  bearing  and 
the  other  near  the  front  of  the  gate.  From  the  point  of  each  angle-iron 
arm,  a  wire  ran  over  a  pulley,  fastened  to  each  post,  to  a  counterbalance 
weight  for  the  gate.  Although  this  gate  never  had  a  fair  tryout,  it  was, 
to  all  appearances,  too  light  to  stand  the  wear,  and  if  made  heavier  would 
have  been  too  cumbersome. 

An  adaptation  of  the  finger  chute,  Fig.  206,  used  in  other  districts 
was  then  tried.  A  shaft  running  through  a  bearing  on  each  post  sup- 
ported four  60-lb.  rails  which  formed  the  fingers.  The  rails  were  held 


266 


DETAILS  OF  PRACTICAL  MINING 


apart  by  short  pieces  of  pipe.  A  triangular  frame  with  a  handle  served 
to  operate  the  gate,  and  at  the  top  of  the  frame  were  three  weights  on 
a  short  crosspiece  which  acted  as  a  counterweight.  This  chute  was  not 
successful  due  to  the  material  handled.  It  was  too  heavy  for  one  man 
to  work  at  times,  even  with  the  counterweight,  and  at  other  times  the 
material  could  not  be  held  in  check. 

The  finger  chute  was  therefore  discarded  and  the  Keating  chute, 
with  the  Minnesota  gate,  was  changed,  as  shown  in  Fig.  209,  to  suit  the 
rock-drift  system  of  development.  The  lower  ends  of  the  rails  are  fast- 
ened to  the  posts  and  the  upper  ends  are  held  by  staples  driven  into 
wooden  plugs,  which  are  firmly  wedged  into  holes  drilled  in  the  back  of 
the  drift.  This  chute  is  now  the  standard  for  the  mine  and  works  well. 
The  back  over  the  chute  marked  B  in  the  figure  was  at  first  made  from 
6  to  8  ft.  long,  but  has  been  cut  down  to  from  2  to  3  ft.,  which  makes  it 


FIG.  209. KEATING  CHUTE  ADAPTED  TO  ROCK  DRIFT. 

much  more  convenient  for  the  man  barring  or  blasting.  The  lip,  which 
is  18  in.  long,  sometimes  catches  on  large  pieces  on  the  top  of  the  cars; 
but  owing  to  the  type  of  cars  used  this  cannot  be  remedied.  A  new 
type  of  car  is  to  be  introduced  which  will  remove  this  trouble. 

Ore-chute  Side  Pocket  (By  Lewis  B.  Pringle). — In  Fig.  210  is  shown 
an  ore  chute  used  by  the  Cananea  Consolidated  Copper  Co.,  in  its  Capote 
mine.  The  chute  was  designed  by  the  geological  department  of  the 
company,  and  was  first  used  in  getting  the  silica  ore  from  the  "  silica 
stope."  The  chute  in  itself  need  not  differ  from  any  of  the  many  chutes 
now  used.  The  feature  newly  introduced  is  an  elevated  pocket  on 
one  side  of  the  chute,  reached  by  a  short  ladder. 

Ordinarily,  if  a  chute  becomes  jammed,  the  jam  must  be  broken  by 
one  of  two  methods,  i.e.,  either  by  discharging  a  piece  of  dynamite  in 
the  chute,  or  by  breaking  the  jam  with  a  crowbar  or  "prod."  The  first 


TIMBER  STRUCTURES 


267 


method  is  frequently  objectionable  because  of  the  danger  of  injuring 
the  chute  and  because  of  the  resulting  fumes.  When  the  latter  method 
is  preferable,  the  arrangement  herein  described  will  prove  to  be  a  time- 
saver  and  a  help  to  the  man  who  is  using  the  crowbar.  The  car-filler 
generally  has  either  to  reach  over  the  partly  filled  car,  or  get  upon  it, 
and  poke  his  bar  up  through  the  chute  gate.  The  arrangement  herein 
described  permits  the  car-filler  to  climb  into  the  adjoining  pocket,  reach 
over  the  planking  shown  in  the  side  elevation  and  get  at  the  seat  of  the 
trouble  more  easily  and  more  quickly  than  otherwise.  Often  the  rock 
jams  at  the  elbow  of  the  chute,  and  the  pocket  herein  described  enables 
a  man  to  reach  this  elbow,  as  he  could  not  if  working  from  below. 

The  erected  chutes  do  not  follow  the  drawing  in  detail;  the  latter 
merely  illustrates  the  idea  and  the  chute  builder  constructs  the  chute  to 
meet  the  required  conditions.  In  building  the  first  chute  of  this  type, 


BIG.    210. — ELEVATIONS   SHOWING   RELATION   OP   POCKET  TO   CHUTE. 

the  sharp  elbow  shown  was  cut  off,  and  the  back  stulls  were  lengthened  a 
foot  or  more.  The  few  dimensions  given  are  more  or  less  standard. 
The  planking  which  keeps  the  rock  from  filling  into  the  pocket,  can  be 
raised  or  lowered  as  necessary,  leaving  enough  room  between  the  top 
plank  and  the  roof  for  a  man  to  work  over.  The  board  that  controls 
the  flow  of  the  ore  is  also  raised  or  lowered  as  required. 

Bulldozing  Chute  and  Underswung  Gate  (By  G.  J.  Jackson). — At 
the  Perseverance  mine  of  the  Alaska  Gastineau  Mining  Co.,  at  Juneau, 
mining  is  conducted  in  large  open  stopes  somewhat  on  the  shrinkage 
system.  Trouble  was  experienced  from  large  rocks  weighing  several 
tons  being  drawn  into  the  chutes;  these  rocks  had  to  be  blasted,  with  the 
result  that  chute  timbers  were  often  broken,  and  a  continual  expense 
incurred  in  the  upkeep  of  the  chutes.  A  chute  with  a  special  bulldozing 


268 


DETAILS  OF  PRACTICAL  MINING 


chamber  fitted  with  grizzly  bars,  was  tried  early  in  1912.  It  proved  a 
complete  success,  over  20,000  tons  of  rock  being  drawn  through  it  with- 
out trouble.  Fig.  211  is  a  section  showing  the  general  arrangement.  The 
80-lb.  rails  used  for  grizzly  bars  are  spaced  2  ft.  apart,  one  end  resting  in 
hitches  cut  in  the  foot-wall  and  the  other  end  on  a  24  X  24-in.  cap.  Any 
rock  passing  through  the  grizzly  can  easily  be  handled  in  the  cars;  the 
larger  rocks  which  remain  on  the  bars  are  drilled  with  a  small  plugger 
machine  and  blasted.  A  ladderway,  not  shown,  leads  up  to  the  bull- 
dozing chamber  from  the  level.  When  the  ore  is  running  freely,  con- 
taining few  large  rocks,  the  grizzly  bars,  over  the  back  pocket,  will  be 
partly  covered.  Should  the  front  grizzly  block  up,  the  small  rock  is  got 


Bulldozing  Chamber 

Grizzlu.80lb.l?a//s 


FIG.  211. — POCKET,  CHUTE  AND  GATE.      PIG.  212. FRONT  ELE- 
VATION OF  GATE  ALONE. 

rid  of  into  the  back  pocket,  and  the  large  rocks  thus  made  accessible 
are  blasted.     The  two  pockets  together  hold  about  25  tons. 

The  arc  chute  gate  shown  in  front  elevation  in  Fig.  21 2,  is  of  the  drop- 
down type.  It  is  counterbalanced  and  is  operated  easily  by  one  man  by  de- 
pressing the  handle.  It  will  handle  any  kind  of  rock  and  will  shut  off  even 
with  a  1-ton  rock  passing  through.  The  operator  stands  on  the  platform 
above  the  cars,  and  is  completely  out  of  danger  from  rocks  falling  from 
the  chute.  A  slide  gate,  not  shown  in  the  sketch,  is  used  above  the  arc 
gate  to  check  the  rock.  The  arc  gate  is  made  of  )4-in.  iron  plate,  18  in. 
wide  and  6  ft.  6  in.  long,  bent  with  a  3-ft.  radius.  This  is  stiffened  for 
its  full  length  by  three  2-in.  angle  irons  riveted  on.  The  two  triangular 


TIMBER  STRUCTURES 


269 


end-pieces  are  made  of  J^  X  3-in.  iron,  reinforced  by  a  piece  of  the  same 
material  fitted  inside  the  arc.  The  two  side  levers  are  of  %-in.  round  iron, 
connected  with  a  %-in.  iron  handle  parallel  with  the  gate.  Two  %Q-in. 
wire  ropes  attached  to  the  end  of  each  lever  and  passing  over  small  sheave 
wheels  on  the  chute  timbers,  support  weights  sufficient  to  balance  the 
gate.  The  gate  is  made  in  the  mine  shop  and  can  be  quickly  set  up  on 
any  chute,  provided  there  is  sufficient  headroom  to  accommodate  the 
operator. 


FIG.    213. ORE    CHUTE    OF   BUGGED    CONSTRUCTION. 

Substantial  Ore  Chute  (By  H.  H.  Hodgkinson). — When  ore  is  dumped 
into  most  ore  chutes  it  strikes  a  direct  blow  almost  at  right  angles  to  the 
front  of  the  chute.  The  chute  shown  in  Fig.  213  is  so  constructed  that 
it  receives  a  glancing  blow,  rather  than  the  full  impact,  and  will  resist 
a  great  deal  of  pounding  and  banging  because  it  is  backed  with  rock  or 
ore. 

The  stulls  and  horizontal  timbers  A,  B  and  C  are  placed  in  hitches 
and  carry  the  chute  and  the  weight  of  the  ore  in  the  chute.  The  timber 


270 


DETAILS  OF  PRACTICAL  MINING 


A  is  bolted  to  the  stulls  as  shown,  while  a  layer  of  6-in.  round  lagging  is 
spiked  in  a  horizontal  position  to  the  stulls.  A  layer  of  6-in.  round 
lagging  is  spiked  to  the  horizontal  timbers  B  and  C,  while  the  lower  ends 
are  supported  by  the  timber  A.  The  lagging  is  trimmed  so  that  a  layer 
of  2-in.  plank  which  is  spiked  to  it  fits  smoothly;  this  insures  a  good  sur- 
face upon  which  to  place  the  %-in.  wrought-iron  plates  so  that  they  will 
not  buckle  and  tear  loose.  The  iron  plates  are  4  X  8  ft.  and  have  coun- 
tersunk holes  for  %-in.  bolts  which  pass  through  the  main  timbers  A, 
B  and  C,  as  shown,  clamping  the  back  of  the  chute  firmly  together,  in 
addition  to  securing  the  plates.  Iron  plates  are  bolted  on  the  sides  of  the 
planks  at  the  mouth  of  the  chute  and  also  to  the  bottom.  The  timbers 
are  stulled  to  stiffen  the  chute,  and  the  space  between  the  front  and  back 
of  the  chute  is  filled  with  ore  or  rock  which  gives  solidity  to  resist  shock. 
Although  the  initial  cost  of  this  chute  is  somewhat  greater  than  that 
of  the  average  chute  used,  its  life  is  many  times  longer.  On  a  number  of 


FRONT    ELEVAT10K  SIDE   ELEVATION 

FIG.    214. DUMP    ARRANGEMENT    FOR    UNDERGROUND    HOIST. 

them  in  use  constantly  for  four  years  and  receiving  hard  treatment  no 
repairs  whatever  have  been  necessary  and  they  are  as  good  as  when  first 
installed  except  for  a  little  wear  at  the  lower  ends  of  the  iron  plates. 

Chute  for  Loading  Car  from  Skip  (By  W.  W.  Shelby). — When  condi- 
tions are  such  that  it  is  desirable  to  have  a  skip  dump  directly  into  cars, 
Fig.  214  shows  a  satisfactory  arrangement  for  an  underground  dump. 
The  width  of  chute  is  1  ft.  less  than  the  length  of  car.  The  middle  par- 
tition serves  two  purposes :  To  distribute  the  ore  so  as  to  utilize  as  much 
car  capacity  as  possible,  and  to  protect  the  chain  across  the  top  of  the 
"middle  dump"  cars.  A  %-in.  iron  plate,  stiffened  by  a  1  X  1  X  M~m- 
angle  iron  is  suspended  in  front  of  the  chute.  This  plate,  the  dimensions 
and  position  of  which  depends  upon  local  conditions,  swings  freely  about 
the  rod  A,  and  deflects  the  few  stray  pieces  of  rock  which  might  other- 
wise go  over  the  car  in  too  rapid  dumping. 


TIMBER  STRUCTURES 


271 


Hanging  Chutes  (By  L.  D.  Davenport). — When,  in  mining  by  the 
top-slicing  system,  the  ore  has  been  sliced  off  down  to  the  last  sublevel 
above  the  main  level,  usually  about  10  to  12  ft.,  it  is  evident  that  an 
ordinary  chute  will  hold  only  about  one  car  of  ore  at  a  time.  It  often 
happens  in  such  cases  that  the  miners  have  to  wait  until  the  trammers 
empty  their  chute  before  they  can  go  on  with  their  work.  To  prevent 
such  waits  a  hanging  chute  was  devised  which  has  been  successfully 
used  in  one  of  the  mines  of  the  Chisholm  district  on  the  Mesabi  range. 
Fig.  215  shows  the  general  construction  of  the  chute.  The  track  from 
the  sublevel  is  carried  by  short  drift  sets,  which  also  support  the  sides 
of  the  chute.  The  chute  bottom  is  made  of  loose  boards  resting  on  30- 
Ib.  rails  which  run  lengthwise  of  the  chute  and  carry  the  greater  part  of 
the  weight.  These  rails  are  hung  to  the  caps  of  the  small  sets  so  as  just 


End     Elevation 


i     i  /  -.-        i 

Side    Elevation 


FIG.    215. HANGING    CHUTES    USED   IN   SUB-LEVEL   MINING. 

to  clear  the  top  of  the  tram  cars  on  the  main  level.  These  chutes  are 
sometimes  made  20  ft.  or  more  in  length  and  hold  a  large  number  of 
cars  of  ore.  One  tram  car  may  be  filled,  or  several  at  the  same  time, 
by  loosening  and  removing  a  few  of  the  bottom  boards. 

Concrete  Storage  Chutes  in  Stopes  (Bull,  American  Institute  of 
Mining  Engineers). — It  has  been  found  economical  at  the  Copper  Queen 
mine  in  Arizona,  for  handling  certain  kinds  of  ore,  to  put  in  concrete 
pockets  and  cylindrical  raises  to  be  used  as  storage  chutes,  since  the 
upkeep  cost  is  practically  nothing,  whereas  with  timber  chutes  this  is 
high.  Fig.  216  shows  a  concrete  pocket  built  particularly  to  handle  sticky 
ores  from  the  Dividend  slice.  It  has  the  shape  of  a  funnel,  with  the 
large  end  downward.  About  30  ft.  above  the  sill,  in  the  top  of  this 
funnel  a  45°  offset  or  baffle  was  put  in,  and  from  this  point  the  raise  was 


272 


DETAILS  OF  PRACTICAL  MINING 


continued  to  a  level  200  ft.  above  the  sill.  This  raise  is  circular  and  lined 
with  concrete,  and  it  is  confidently  .believed  that  this  type  of  pocket 
will  materially  lower  the  cost  of  handling  the  ore. 

Chute  Reinforced  with  Angles  (By  Albert  G.  Wolf).— In  mining  by 
the  shrinkage  method,  large  boulders  are  often  covered  in  the  stopes. 
These  boulders  eventually  work  down  to  the  chutes,  and  to  remove 


j 


25-8 

SECTION  A-A; 


SECTION   B-8 


FIG.    216. — VERTICAL    SECTIONS    OF    A    CONCRETE-LINED    STOPE    POCKET. 

them  it  is  necessary  to  resort  to  blasting,  which  will  weaken  or  destroy 
the  chute  timbers.  A  simple  reinforcement  against  such  injury  is  shown 
in  Fig.  217.  Pieces  of  K6~m-  sheet  iron  are  cut  to  fit  the  chute  sides, 
and  to  this  sheet  iron  are  riveted  pieces  of  J^  X  2-in.  angles,  forming 
both  braces  and  cleats  to  hold  the  chute  boards.  These  sheets  or  liners 
are  then  fastened  to  the  inner  sides  of  the  chutes  by  spiking  or  bolt- 
ing. The  exact  length  of  the  angle  braces  is  immaterial,  A  piece  of 


TIMBER  STRUCTURES 


273 


sheet  iron  covering  the  bottom  of  the  chute  will  also  add  greatly  to  its 
life. 

Quincy  Rockhouse  Loading  Chutes  (By  L.  Hall  Goodwin). — The 
Quincy  method  of  loading  stamp  rock  from  the  storage  bins  at  the  mine 
into  cars  for  transportation  to  the  mill  is  unique  among  methods  used 
at  the  Lake  Superior  mines  in  that  the  chute  aprons  are  operated  by 
compressed  air.  Fig.  218  illustrates  the  chute  mechanism.  The  air 
cylinder  is  direct  connected  to  one  corner  of  an  irregularly  shaped,  four- 
cornered  steel  plate,  the  other  three  corners  of  which  are  connected  by 
levers  with  the  lower  apron  of  each  chute  and  a  hand  lever,  respectively ; 
the  plate  is  pivoted  so  that  the  various  levers  have  the  right  amount  of 
play.  The  hand  lever  is,  of  course,  thrown  whenever  the  aprons  are 


PIG.    217. STEEL    PROTECTION    APPLIED    TO    CHUTE. 

operated  but  it  is  of  use  only  in  emergency,  when  the  air  accidentally 
goes  off;  the  aprons  cannot  be  operated  easily  by  hand,  but  are  opened 
and  closed  quickly  by  the  air  cylinders.  The  air  cocks  are  centrally 
placed  in  a  niche  left  in  the  concrete  bin  foundation  midway  of  the  tunnel ; 
this  niche  is  just  large  enough  to  allow  the  operator  room  to  work  com- 
fortably. There  is  one  air  cock*  for  each  cylinder,  that  is,  for  each  pair 
of  chutes,  and  they  are  arranged  on  the  two  sides  of  the  operator's 
niche  corresponding  to  the  position  of  the  chutes  they  control.  The 
air  cocks  and  pipes  are  arranged  to  admit  air  to  either  end  of  the  cylinders. 
The  operation  of  loading  is  as  follows:  The  string  of  cars  is  pushed 
through  the  tunnel  by  the  switching  locomotive  and  left  there,  the 
grade  of  the  track  being  such  that  the  cars  may  be  started  easily  when 
the  brakes  are  released.  Cars  are  loaded  by  two  men,  one  of  whom  oper- 

18 


274 


DETAILS  OF  PRACTICAL  MINING 


ates  the  chute  aprons;  the  other  rides  the  forward  car  and  by  use  of  the 
brake  keeps  the  cars  in  slow  but  steady  motion,  the  aim  being  not  to 
allow  them  to  come  to  a  standstill  because  they  might  not  start  again 
of  their  own  accord.  As  soon  as  an  empty  car  comes  under  the  end 
chutes  the  aprons  of  that  pair  of  chutes  are  opened  and  remain  open 
until  the  car  is  about  to  pass  from  under  them;  the  filling  of  the  car  is 
completed  as  it  passes  along  under  the  other  chutes,  and  its  load  is  finally 
topped  off  by  a  few  splashes  from  the  last  pair  of  chutes.  To  accomplish 
this,  several  pairs  of  chutes  must  often  be  open  at  once,  and  the  operator 
must  be  alert  to  avoid  spilling  rock  on  the  track;  his  work  is  not  dif- 
ficult, however,  as  it  consists  of  simply  turning  air  cocks.  Air  is  supplied 

from  the  main  underground  system;  between  shifts  or  at  other  times 

i 

'Bottom  ofI-Beamsl3above  Kail  A 


Counterbalance 
Chutes  made  of  j sheet  iron  and 3* channels. 
Lever  arms  made  of  1$' pipe,  except  hand 
lever 
Upper  aprons  work  by  gravity  only. 


FIG.    218. LOADING    CHUTES    AT  QUINCY's    STEEL    STORAGE    BINS. 

when  the  large  air  compressors  are  not  working,  a  small  Westinghouse 
air  pump  takes  the  load,  it  being  adjusted  to  start  and  stop  automatically 
whenever  the  pressure  in  the  underground  system  falls  below  or  exceeds 
a  certain  amount. 

This  method  permits  more  rapid  loading  than  does  the  usual  one, 
with  which  it  is  necessary  to  stop  each  car  for  some  time  under  the 
chutes.  This  is  true  not  so  much  because  of  their  operation  by  air, 
however,  as  because  the  chutes  are  located  in  pairs  on  opposite  sides  of 
the  track  and  there  are  more  of  them  than  usual. 

Underswung  Gate  (By  J.  R.  Thoenen). — Fig.  219  shows  the  front  and 
side  views  of  a  chute  and  gate  for  use  where  the  bin  supplies  mixed  fine 
and  coarse  ore.  The  chute  proper  is  made  of  one  piece  of  J^-in.  steel 


TIMBER  STRUCTURES 


275 


plate,  the  bottom  extending  6  in.  into  the  bin  to  protect  it  from  wear  of 
running  ore.  Two  wing  plates  of  J^-in.  steel  are  riveted  on  the  vertical 
sides  to  protect  the  sides  of  the  chute,  and  for  the  same  purpose,  a  piece 
of  angle  steel  may  be  placed  on  top  of  the  opening.  In  this  instance, 
the  bottom  of  chute  is  16  in.  long,  but  may  be  altered  to  suit  the  existing 
arrangement  of  timbers. 

The  gate  is  hung  on  a  IJ^-in.  round-iron  axle  supported  in  holes  bored 
through  the  sides  of  the  chute.  The  sketch  shows  the  chute  open  and 
the  gate  down.  The  top  of  the  gate  itself  forms  the  lip  of  the  chute. 
A  timber  is  placed  under  the  gate,  so  that  when  open,  the  gate  rests  upon 
it  and  is  flush  with  the  bottom  of  the  chute.  The  gate  is  worked  by  a 
short  detachable  lever  (not  shown),  which  is  rounded  at  one  end  to  fit  in 


FIG.    219. STEEL    CHUTE    AND    GATE    ASSEMBLED. 

the  hole  in  the  short  piece  riveted  to  the  bottom  of  the  chute  gate.  A  hole 
through  the  lever  fits  over  the  end  of  the  axle  and  forms  the  fulcrum. 
Washers  and  pins  are  provided  to  keep  the  axle  in  place.  The  gate  is 
made  of  two  pieces  of  J^-in.  steel  plate,  one  bent  in  the  arc  of  a  circle  of 
1  ft.  radius,  the  other  flat  with  one  edge  turned  over  2  in.  at  a  little  less 
than  a  right  angle.  These  two  plates  are  riveted  together  with  counter- 
sunk rivets.  The  gate  bearing  for  the  axle  is  provided  by  a  small  web 
piece  riveted  at  each  end  to  the  upper  plate  and  lower  brace.  Three 
Y±  X  2-in.  braces  support  the  under  side  of  the  gate.  When  the  gate  is 
well  centered,  so  that  the  arc  forms  a  true  circle  with  the  center  of  the 
axle  as  its  center,  there  is  practically  no  trouble  with  fines  causing  the 
gate  to  stick. 

Supporting  Sliding  Gate  and  Lever. — In  Fig.  220  is  shown  the  manner 
of  supporting  the  lever  of  a  chute  gate  used  on  some  of  the  chutes  in  the 
mines  of  the  St.  Louis  Smelting  &  Refining  Co.,  in  southeastern  Missouri. 


276 


DETAILS  OF  PRACTICAL  MINING 


The  gate  lever  is  carried  by  two  iron  brackets  bolted  to  the  uprights  of 
the  chute  and  is  bent  up  so  as  to  be  out  of  the  way  of  miners  passing  along 
the  track;  and  is  then  bent  downward  again  so  as  to  be  within  reach  of 
the  miner  on  the  opposite  side  of  the  drift.  The  carrying  braces  are 
bent  in  so  that  they  are  separated  by  a  space  only  as  wide  as  the  thickness 
of  the  lever  bar,  at  the  point  where  the  bolt  goes  through. 

A  slide  gate  is  used  that  runs  in  an  angle-iron  guide  fastened  through 
the  side  planks  to  the  main  timbers  of  the  chute.  The  lever  is  connected 
by  a  pair  of  clevises  to  the  gate,  but  it  also  extends  far  enough  beyond 
the  gate  to  come  over  it  and  to  shove  it  down  to  its  seat  in  case  it  should 


FIG.    220. GATE    LEVER   EXTENDING    ACROSS   DRIFT. 

stick.  The  gate  works  well  and  no  more  "runs"  of  ore  occur  than  would 
be  the  case  with  any  top-closing  gate.  The  manner  of  supporting  the 
lever  allows  it  to  be  brought  out  straight  in  front  of  the  gate  so  that  the 
loader  can  look  up  into  the  chute  as  the  ore  runs  out  and  shut  or  open 
the  gate  as  needed.  The  bending  of  the  lever  up  into  a  goose  neck  so 
that  over  the  track  it  is  above  a  man's  head  when  the  gate  is  only  half 
closed,  removes  any  objection  to  having  the  gate  lever  extend  across 
the  drift. 

Pneumatic  Underswung  Arc  Gate  (By  J.  R.  McFarland). — At  the 
Cactus  mine  of  the  South  Utah  Mines  &  Smelters,  Beaver  County,  Utah, 
a  pneumatically  operated  ore-chute  gate  was  used.  The  gate,  as  shown 
in  Fig.  221,  was  operated  by  moving  a  lever  controlling  a  four- way 


TIMBER  STRUCTURES  277 

valve.  To  the  bottom  corner  of  the  chute  was  attached  the  supporting 
shaft.  The  door  was  constructed  of  a  square  sheet  of  boiler  plate  the 
width  of  the  chute,  bent  in  an  arc  with  the  face  up,  and  supported  on  the 
shaft  by  two  legs,  so  as  to  revolve  about  the  shaft  as  an  axis.  To  the 
side  of  the  door  on  the  underside  of  the  chute,  was  attached  a  piston 
working  in  a  cylinder.  The  piston  rod  was  hinged  at  the  top  and  the 
cylinder  at  the  bottom  so  as  to  allow  the  necessary  play. 

Air-lift  Finger  Chute  Gate. — For  most  of  the  important  ore  chutes 
of  the  Oliver  mines,  at  Ely,  Minn.,  a  modified  finger  gate  with  a  homemade 
air  lift  is  used.  The  drawing,  Fig.  222,  represents  the  arrangement  for 


FIG.    221. GATE    OPERATED   BY    AIR    CYLINDER    HINGED   BELOW. 

one  of  the  underground  skip-loading  chutes.  The  fingers  of  the  gate  are 
made  of  rails,  the  weight  depending  chiefly  on  the  stock  of  material  which 
it  is  desired  to  use  up.  In  some  cases,  instead  of  bending  the  rails,  they 
are  made  in  two  pieces  and  riveted  together.  The  lift  cylinder  is  made 
of  a  piece  of  4-in.  pipe.  One  end  of  this  is  closed  with  an  ordinary  cap 
and  the  lift  is  hung  by  this.  The  other  end  is  closed  with  a  reducer  which 
contains  an  inlet  for  the  air,  and  a  stuffing  box  through  which  the  rod 
runs.  The  piston  forming  the  end  of  the  rod  consists  of  a  leather  gasket 
with  turned-down  edges,  between  two  metal  disks  with  nuts  on  each  side. 
The  release  of  the  air  to  drop  the  gate  is  effected  by  the  same  valve  that 
admits  the  air.  This  is  a  three-way  valve  made  from  an  ordinary  stop- 
cock. The  body  and  plug  are  drilled  as  shown  in  the  detailed  drawing. 
Position  A  shows  the  valve  open  to  the  compressed-air  supply  for  raising 
the  gate.  By  turning  90°,  B,  the  drilled  hole  in  the  plug,  registers  with 
the  passage  of  the  cylinder  and  the  part  through  the  plug  registers  with 
the  hole  drilled  in  the  body,  thus  permitting  the  air  to  exhaust. 


278 


DETAILS  OF  PRACTICAL  MINING 


Underswung  Rack-operated  Arc  Gate  (By  Walter  R.  Hodge). — The 
chute  gate  shown  in  Fig.  223  is  of  the  underswung  arc  type,  hung  from 
heavy  castings,  which  are  bolted  to  the  timbers  of  the  chutes  or  bin  and 
not  to  the  chute  lip,  as  they  often  are.  These  suspending  members  are 
made  unusually  heavy  and  extend  well  out  from  the  face  of  the  timbers 


.•To  Cylinder 


GATE  fit  LIFT. UNDERGROUND 
FIG.    222. ASSEMBLY    OF    GATE    AND    SECTION    OF   VALVE. 

to  allow  the  top  of  the  door  to  clear  the  bottom  of  the  chute  at  the  extreme 
open  position.  The  method  of  operating  the  gate  is  perhaps  a  little 
unusual.  Two  racks  are  fastened  by  pins  to  lugs  riveted  to  the  lower  edge 
of  the  door.  The  racks  are  inverted,  teeth  down,  and  so  are  protected 
from  dirt  or  fines.  No  lubricant  is  used.  Each  of  these  racks  works  on 


TIMBER  STRUCTURES 


279 


a  pinion,  keyed  to  a  shaft.  This  shaft  lies  back  and  under  the  chute  and 
turns  in  gas-pipe  bearings  set  in  the  timbers.  A  crank  operates  the 
shafting  and  pinions.  One  revolution  of  the  crank  raises  or  lowers  the 
door  6  in.  and  effectually  checks  any  rush  of  ore.  The  rock  caught  on 
the  closing  edge  of  the  door,  instead  of  clogging  the  door,  is  thrown  back 
into  the  chute  by  the  rising  door  or  pushed  into  the  car.  The  whole 
mechanism  is  simply  and  easily  operated  by  one  man.  Gates  of  this  type 
are  used  at  the  Burra  Burra  mine  of  the  Tennessee  Copper  Co.  in  connec- 
tion with  large  pocket  chutes  from  which  tram  cars  are  loaded. 

Safety  Lever  for  Arc  Gate  (By  E.  W.  R.  Butcher) . — In  its  effort  to  re- 
duce accidents,  the  Republic  Iron  &  Steel  Co.,  on  the  Mesabi  range,  has 
introduced  among  numerous  safety  devices,  an  operating  lever  for  the 


I  Bolts 

~TC 


Chute 


I-  Clearance 
Forged  hinge  riveted 
to  door  ,»Z  ,.    .•''     ,„ 

with  Pawl      & 


l&'long 


Hearings 


CJ.rack,fO 


roller  to 
guide  rack 


FIG.    223. ELEVATIONS    OF  CHUTE    AND    RACK-OPERATED    GATE. 

underground  arc-type  chute  gates.  Fig.  224  shows  its  details  and  ar- 
rangement. Usually  such  a  lever  arm  is  attached  directly  to  a  trunnion 
of  the  gate.  The  arm  extends  across  the  drift  and  where  motors  are  used, 
it  is  necessary  for  the  man  emptying  the  chute  to  stand  between  the  cars. 
In  this  position,  he  is  likely  to  be  caught  between  the  car  and 
the  arm  should  the  train  move  unexpectedly.  Furthermore,  while, 
as  a  rule,  the  chute-man  is  required  to  remove  the  arm  when  the  chute 
is  emptied,  if  he.  fails  to  do  so  it  is  likely  to  strike  anyone  riding  past  on 
the  motor,  and  to  cause  a  serious  accident. 

With  the  device  here  shown,  the  lever  arm  is  on  the  side  of  the  drift, 
making  it  unnecessary  for  the  chute-man  to  stand  between  the  cars  and 
largely  doing  away  with  the  danger  of  accident.  The  ends  of  the  gate 
arm,  of  the  cap  arm  and  of  the  double-jaw  connecting  piece  are  fitted  with 
several  connecting  holes  by  which  the  arms  can  be  adjusted  to  the  posi- 


280 


DETAILS  OF  PRACTICAL  MINING 


tions  which  permit  the  most  satisfactory  operation.  Placing  the  con- 
necting end  of  the  gate  arm  in  a  horizontal  position  or  at  a  slight  angle 
above  the  horizontal  and  the  connecting  piece  of  the  cap  arm  at  45°, 
gives  the  best  results.  The  ends  of  the  connecting  arms  are  made  round 
and  the  holes  in  them  are  made  a  little  larger  than  the  holding  pins,  so 
as  to  prevent  binding.  The  measurements  given  are  for  a  chute  30 
in.  wide  in  a  drift  7  ft.  wide.  The  main  dimensions  can  be  easily  changed 
to  suit  any  ordinary  width  of  chute  or  drift. 


Cap  Arm 


Double-jaw  connecting 


piece 


JrH 


4* 

J^ouncf 


H^<- 
-"-  -  H<  -  --  --j-'<5- - — -  >i  JT~  T 

Gate  Arm 

K. 


Connecting 

Lever  Piece 

Arm 

FIG.    224. ARRANGEMENT    FOR    SAFELY    CONTROLLING    CHUTE    GATES. 


SKIP  POCKETS 

Hydraulically  Operated  Skip  Pockets  (By  Clarence  M.  Haight). — 
Fig.  225  shows  the  general  arrangement  of  the  steel  ore-loading  pockets 
in  use  in  the  Palmer  shaft  of  the  New  Jersey  Zinc  Co.'s  mine  at  Franklin 
Furnace,  N.  J.  The  pockets  are  the  design  of  R.  M.  Catlin,  superintend- 
ent. The  arrangement  includes  a  loading  pocket,  and  between  this  and 
the  rock  ore-bin,  a  chute  and  gate.  The  loading  pocket  holds  one  skip- 
load  of  ore  only;  the  upper  chute  feeds  the  loading  pocket  and  its  gate 
cuts  off  the  ore  supply  therefrom  when  the  skip  is  filling.  Water  from 
the  column  pipe  in  the  shaft  furnishes  power  to  the  hydraulic  ram  which 


TIMBER  STRUCTURES 


281 


operates  the  gate  levers.  The  direction  of  the  movement  of  the  ram  is 
controlled  from  the  loading  platform  by  an  easily  operated  four-way  valve. 
Water,  after  use,  flows  out  through  a  waste  pipe  from  the  valve. 

When  closed,  the  apparatus  stands  as  shown  in  the  drawing.  The 
lower  door  is  closed  and  the  lip  A  of  the  upper  chute  gate  is  drawn  back 
beyond  the  bottom  of  the  chute.  This  allows  the  ore  to  run  into  the 
bottom  or  loading  pocket  until  that  is  rilled,  and,  as  the  angle  of  repose  of 
the  ore  is  then  reached,  the  movement  of  the  ore  stops  with  both  the  lower 
pocket  and  the  chute  full.  When  the  empty  skip  is  spotted  at  the  door 
of  the  loading  pocket,  the  controlling  valve  is  reversed.  The  hydraulic 


PIG.    225. SIDE    ELEVATION    OF    SKIP    POCKET. 

ram  moves  out  along  the  arc  shown,  its  connection  point  R  moving  toward 
the  position  R' }  this  moves  the  lip  A  around  its  pivots  P  toward  A', 
closing  off  the  chute  so  that  no  more  ore  can  go  into  the  loading  pocket. 
Meanwhile,  the  rod  G  is  pulled  forward  and  up  toward  the  position  in- 
dicated by  the  line  G'.  This  motion  moves  the  lever  arms  B  and  C, 
which  link  the  rod  G  to  the  lower  pocket  door,  so  that  the  pins  H  and  / 
advance  toward  the  positions  H'  and  /'.  The  door  D  of  the  loading 
pocket  is  held  against  the  mouth  of  the  pocket  by  two  arms,  pivoted 
at  Q  and  E.  The  movement  of  the  arms  B  and  C  forces  the  door  toward 
the  open  position  D'.  This  position  is  reached  at  the  end  of  the  stroke 
of  the  hydraulic  ram.  As  this  door  opens,  the  ore  runs  from  the  pocket 


282 


DETAILS  OF  PRACTICAL  MINING 


into  the  skip.  In  this  operation,  the  advance  of  the  lip  A  is  more  rapid 
at  first  than  the  movement  of  the  door  D,  so  that  it  has  cut  off  the  ore 
lying  in  the  chute  before  the  loading  pocket  begins  to  discharge  to  the 
skip.  In  like  manner,  on  reversing  the  ram,  the  door  D  moves  the  more 
rapidly  at  first,  so  that  it  is  closed  tight  before  the  lip  A  has  retreated 
far  enough  to  allow  any  ore  to  run  into  the  pocket.  Hence,  all  danger  of 
an  excess  of  ore  running  over  the  skip  and  down  the  shaft  is  avoided. 
The  lip  A  cannot  jam,  because  it  cuts  in  from  under  the  chute  when  clos- 
ing and  so  cannot  catch  on  a  chunk  of  ore;  while,  as  the  door  D  does  not 
close  until  the  pocket  is  empty,  there  is  nothing  for  that  to  catch  on. 

One  man  only  is  needed  to  operate  a  pair  of  pockets,  as  the  valves 
work  easily.  A  second  man  is  stationed  in  the  shaft,  below  the  loading 
platform,  to  trim  the  skip  in  case  a  large  chunk  lies  on  the  top  of  the  load 


M 

r 

ir        \ 

'       r 

1 

ir 

8     .                 1 

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S 

1 

1£; 

2"Shaff-    I  . 

Air, 

-l2"Wheel  ' 

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PipeY 

=: 

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Si                     > 

ft- 

F 

*            1     •   i 

S         '       5 

i      1  | 

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ii 

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If    i 

II     i 

ii    i 
4-  ! 

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tlf 

*      I   ^ 

i   !  k 

:     4^[ 

1 

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10 

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Sk 

P 

7i.-^...>, 

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)'<••-•&"->  i 

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J  *'1-£-2~~> 

Skip 

fe 

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y 

FIG.    226. BINS    AND    LOADING    CHUTES,    HANCOCK    NO.    2   SHAFT   STATIONS. 

and  projects  over  the  back  or  the  sides  of  the  skip.  The  operation  of  these 
pockets  is  easy  and  rapid.  With  skips  averaging  about  6  tons  to  the  load, 
over  2000  short  tons  has  been  hoisted  in  eight  and  one-half  hours. 

Hancock  Skip  Pockets  (By  Claude  T.  Rice). — The  details  of  the 
construction  of  the  doors  to  the  skip  pockets  in  the  Hancock  Shaft  in 
the  copper  district  of  Michigan  are  shown  in  Fig.  226.  The  chutes  are 
equipped  with  an  apron  to  bridge  the  gap  between  the  bin  chute  and  the 
skip.  This  apron  is  raised  by  a  handwheel  and  a  system  of  chain-driven 
pulleys.  The  apron  falls  by  gravity  and  catches  on  the  edge  of  the  skip, 
while  the  skip  tender  has  to  raise  it  by  means  of  the  wheel.  These 
wheels  can  be  whirled  rapidly,  making  the  pawls  sing  as  they  skim  over 
the  ratchet  and  the  apron  is  moved  away  faster  than  would  at  first  be 
expected. 

The  gate  proper  of  the  bin  is  a  corrugated  plate  operated  by  an  air 


TIMBER  STRUCTURES 


283 


cylinder.  Air  is  admitted  under  the  piston  only  for  the  raising  of  the  gate, 
while  the  lowering  is  regulated  by  the  opening  of  another  valve  which 
controls  the  escape  of  the  air  from  under  the  piston.  The  gate  plate  is 
carried  from  a  crosshead  that  moves  in  the  same  steel  guides  as  the  plate 
itself.  The  guides  are  bolted  to  the  posts  of  the  sets  put  in  to  carry  the 
front  lining  of  the  bin.  At  the  bottom  of  the  guides  are  stops  to  keep  the 
gate  from  touching  the  bottom  of  the  discharge  chute;  if  it  did  there  would 
be  a  tendency  for  the  gate  plate  to  bind  in  its  guides,  owing  to  the  fact 
that  the  chute  bottom  is  sloping.  A  short  chain  carries  the  plate  from 
the  crosshead,  while  the  crosshead  connects  directly  to  the  piston  of  the 
air  cylinder.  This  cylinder  is  placed  so  that  the  top  comes  just  a  little 
above  the  floor  of  the  station  and  is  carried  by  the  floor. 


FIG.    227. — EMERGENCY   GATE    FOR   SKIP    POCKET. 

The  reason  for  corrugating  the  gate  is  to  diminish  the  friction  of  the  ore, 
since  the  pieces  of  ore  have  a  tendency  to  bridge  across  the  corrugations 
and  touch  only  the  high  places.  The  gate  opens  easily,  and  its  weight, 
together  with  the  weight  of  the  crosshead  and  the  plunger  of  the  air 
cylinder,  closes  it.  In  order  to  allow  the  men  to  lift  without  any  danger 
the  dogs  on  the  ratchet  that  controls  the  descent  of  the  apron,  the 
dogs  are  provided  with  handles. 

Emergency  Ore  Gate  (By  L.  D.  Davenport). — In  one  of  the  mines  of 
the  Chisholm  district,  on  the  Mesabi  range,  considerable  difficulty  was 
experienced  in  cutting  off  the  flow  of  ore  from  the  underground  pocket 
as  soon  as  the  skip  was  full.  The  emergency  gate,  shown  in  Fig.  227, 
was  designed  to  overcome  this  trouble  and  is  now  in  general  use  in  the 
mines  in  this  district.  As  shown  in  the  accompanying  sketch,  the  gate 
consists  of  a  simple  %-in.  iron  plate  8  in.  wide  and  long  enough  to  cover 


284 


DETAILS  OF  PRACTICAL  MINING 


the  end  of  the  chute.  It  is  supported  in  such  a  manner  that  it  can  be 
instantly  dropped  over  the  end  of  the  chute  and  thus  stop  the  ore  in  case 
an  obstruction  prevents  the  quarter  pan  from  closing  down  tight. 


HEADFRAMES 

Headframe  with  Guy-rope  Bracing. — The  headframe  at  the  No.  4 
shaft  of  the  St.  Louis  Smelting  &  Refining  Co.  in  southeastern  Missouri, 
is  approximately  70  ft.  high,  and  no  bracing  legs  are  used  in  the  con- 
struction. The  frame  is  surrounded  by  the  shaft  house  with  a  landing 
platform  for  pulling  off  the  cars  at  the  level  of  the  top  of  the  bins,  which 
are  about  30  ft.  high,  but  this  shaft  house  and  bin  do  not  aid  in  steadying 

TABLE  I. — TIMBER  LIST 


Number 

Mark 

Size 

Length 

Number 

Mark 

Size 

Length 

3 

A 

8  X  8  in. 

28  ft.  0  in. 

2 

G4 

6X  Sin. 

9ft.    Oin. 

1 

A1 

8  X  8  in. 

20  ft.  0  in. 

1 

G' 

6X  Sin. 

6ft.    3  in. 

8 

A2 

8X  8  in. 

4  ft.  0  in. 

4 

H 

4X  6  in. 

11  ft.    8  in. 

6 

B 

8  X  8  in. 

20  ft.  0  in. 

12 

H1 

2X  3  in. 

2ft.    5  in. 

8 

B1 

8X  Sin. 

4  ft.  2  in. 

2 

H2 

2X  3  in. 

1ft.    Oin. 

1 

C 

8  X  8  in. 

20  ft.  0  in. 

4 

H3 

4X  4  in. 

3ft.    Oin. 

1 

C1 

8X  Sin. 

15  ft.  0  in. 

1 

H4 

4X  4  in. 

4ft.    9  in. 

•    2 

C* 

8  X  8  in. 

16  ft.  0  in. 

1 

H* 

3X  3  in. 

6ft.    3  in. 

2 

C3 

8X  Sin. 

20  ft.  0  in. 

1 

H6 

3X  3  in. 

11  ft.    8  in. 

2 

0 

8X  8  in. 

5  ft.  4  in. 

1 

H7 

3X  3  in. 

5ft.    7  in. 

2 

0 

8  X  8  in. 

6  ft.  8  in. 

2 

H« 

2X  3  in. 

6ft.    6  in. 

2 

C6 

8X  Sin. 

12  ft.  2  in. 

2 

H9 

2X  3  in. 

6  ft.    3  in. 

2 

C7 

8  X  8  in. 

11  ft.  5  in. 

20 

Hio 

2X  Sin. 

7ft.    Oin. 

3 

D 

6X10  in. 

12  ft.  9  in. 

1 

H11 

3X  3  in. 

33ft.    Oin. 

3 

DI 

6X10  in. 

22  ft.  0  in. 

2 

I 

2X10  in. 

36  ft.    4  in. 

4 

D2 

6X10  in. 

4  ft.  4  in. 

5 

I1 

3X  4  in. 

5  ft.    4  in. 

4 

D3 

6X10  in. 

lift.  4  in. 

1 

I2 

2X  3  in. 

2  ft.    3  in. 

3 

E 

8X  Sin. 

16  ft.  0  in. 

1 

I3 

2X  3  in. 

12ft.    6  in. 

1 

E1 

8X  Sin. 

9  ft.  8  in. 

1 

I4 

2X  3  in. 

4ft.    Oin. 

3 

E2 

8X  Sin. 

7  ft.  0  in. 

1 

I5 

2X  3  in. 

lift.    2  in. 

4 

E3 

8X10  in. 

4  ft.  2  in. 

1 

I6 

2X  3  in. 

2ft.    Oin. 

3 

E* 

8X  Sin. 

6  ft.  3  in. 

38 

I7 

l^XlOin. 

1ft.    7  in. 

4 

F 

6  X  10  in. 

7  ft.  6  in. 

1 

P 

6X10  in. 

1ft.    4  in. 

3 

F1 

5  X  8  in. 

lift.  2  in. 

4 

J 

6X  4  in. 

3ft.    Oin. 

5 

F2 

5X  8  in. 

9  ft.  6  in. 

2 

J1 

6X  4  in. 

2ft.    6  in. 

2 

F3 

5X  Tin. 

9  ft.  6  in. 

20 

K 

3X  9  in. 

10ft.    2  in. 

1 

F4 

4  X  8  in. 

6  ft.  8  in. 

14 

K1 

3X  9  in. 

5ft.  11  in. 

2 

G 

3X10  in. 

6  ft.  0  in. 

14 

K2 

3X  9  in. 

various 

2 

G1 

3X10  in. 

12  ft.  0  in. 

13 

K3 

3X  9  in. 

9  ft.  8  in. 

6 

G2 

3X10  in. 

6  ft.  0  in. 

3 

L 

4X  4  in. 

4  ft.  6  in. 

3 

G3 

8  X  8  in. 

8  ft.  0  in. 

3 

L1 

4X  4  in. 

10  ft.  6  in. 

TIMBER  STRUCTURES 


285 


the  structure.  The  bracing  is  obtained  by  four  %-in.  guy  ropes  that  are 
anchored  to  concrete  deadmen.  The  guy  ropes  are  tightened  by  turn- 
buckles  or  else  by  pulling  the  rope  back  on  itself  after  passing  around  a 
small  sheave  anchored  to  the  deadman.  This  wheel  is  large  enough  to 
permit  the  rope  to  be  pulled  around  it  without  injury,  by  a  block  and  fall 
fastened  to  the  end  of  the  rope  and  attached  to  the  rope  itself.  This  is 
the  best  way  of  tightening  the  guy  rope. 

The  ore  is  hoisted  on  one-deck  cages  in  1 -ton,  cars,  and  little  trouble 
is  experienced  from  vibration  of  the  headframe.  There  are  several  of 
these  headframes  in  the  district. 

A-type  Timber  Headframe  (By  G.  A.  Denny). — The  headframe  rep- 
resented in  Fig.  228  is  one  installed  at  a  Mexican  mine.  It  was  designed 
for  a  shaft  inclined  at  65°,  for  a  load  of  4000  Ib.  and  a  maximum  rope 
speed  of  460  ft.  per  minute.  The  cost  of  erection  in  Mexican  currency 
was  as  given  in  Table  III.  Tables  I  and  II  give  bills  of  materials  for 
timber  and  iron. 


TABLE  II. — BOLT  AND  WASHER  LIST 


No. 

Mark 

Bolts 

Length 

Washers 

Type 

Size 

No. 

Angle 

1 

a 

B 

IK  in. 

15  ft.    8  in. 

2 

82° 

1 

a1 

B 

iMin. 

12ft.    8  in. 

2 

82° 

2 

b 

B 

IK  in. 

10ft.    Oin. 

4 

flat 

2 

c 

B 

IK  in. 

10  ft.    3  in. 

2 

flat 

2 

65° 

1 

c1 

B 

1^  in. 

9  ft.    9  in. 

1 

flat 

1 

65° 

3 

d 

B 

1      in. 

9  ft.    6  in. 

6 

45° 

6 

d1 

B 

Kin. 

7ft.    6  in. 

12 

flat 

3 

d* 

A 

Kin. 

6ft.    Oin. 

6 

flat 

6 

e 

A 

Mm. 

1  ft.  10  in. 

12 

65° 

6 

e1 

A 

Hin. 

2ft.    Sin. 

12 

65° 

6 

e2 

A 

Min. 

3  ft.    0  in. 

12 

65° 

21 

f 

A 

Kin. 

1  ft.    5  in. 

42 

flat 

3 

f1 

A 

%in. 

1ft.    7  in. 

6 

flat 

21 

g 

A 

H  in. 

1  ft.    1  in. 

11 

g1 

A 

Min. 

1  ft.    8  in. 

13 

flat 

72 

g2 

A 

Min. 

0  ft.  11  in. 

3 

h 

B 

/^       AAJ 

M  in. 

2ft.    3  in. 

6 

flat 

18 

j 

A 

Min. 

0  ft.  11  in. 

18 

flat 

6 

k 

C 

see  drawing 

3 

flat 

3 

72° 

33 

m 

D 

1      in. 

66 

flat  (see 

drawing) 

286 


DETAILS  OF  PRACTICAL  MINING 


TIMBER  STRUCTURES  287 

TABLE  III. — COSTS 

Pesos 

Timber  (at  50  pesos  per  M) 230 

Carpenters  (at  3  pesos  per  day) 772 

Smiths  (at  2.50  pesos  per  day) 92 

Mechanics  (at  3  pesos  per  day) 65 

Iron  plates  and  bolts 293 

Concrete  foundations 113 

Laborers 70 

Freight 35 

Administration . .             375 


Total  cost 2045 

Concrete  Headframe  with  Fleeting  Device  (By  L.  0.  Kellogg).— 
The  flat-lying  shaft  of  the  Sterling  Iron  &  Railway  Co.  in  southeastern 
New  York  reaches  the  surface  at  an  angle  only  a  little  greater  than  the 
slope  of  the  ground.  The  hoist  is  set  on  the  hill  about  100  ft.  above  the 
collar  and  the  dump,  bin  and  headframe,  built  in  this  space,  at  no  place 
rise  more  than  12  or  15  ft.  above  the  ground.  There  is  thus  no  use  for  a 
high  headframe  and  all  that  is  used  is  a  concrete  foundation  under  the 
sheaves  and  some  channels  to  support  the  track.  The  general  arrange- 
ment is  shown  in  two  elevations  in  Fig.  229.  The  10-in.  channels  ex- 
tend toward  the  shaft  collar  and  carry  crossties  on  which  the  rails  rest. 
The  centers  of  the  sheaves  and  of  the  drums  being  so  close  together  and 
the  2500  ft.  of  rope  requiring  several  wraps  on  the  3  X  6-ft.  drums,  it 
is  evident  that  smooth  winding  could  not  be  had  without  some  provision 
for  taking  care  of  the  fleet.  For  this  reason,  the  sheaves  are  made  to 
revolve  on  the  shaft  which  is  held  fixed,  contrary  to  the  more  usual 
practice  of  keying  the  sheave  to  the  shaft  and  allowing  the  latter  to  re- 
volve in  bearings.  The  sheave  is  consequently  free  to  move  laterally 
and  thus  follow  the  rope  in  its  travel  across  the  face  of  the  drum.  The 
correspondence  is  not  perfect,  the  10-in.  hub  of  the  sheave  reducing  its 
possible  lateral  travel  to  28  or  30  in.  while  the  rope  travels  36  in.  across 
the  drum.  In  practice,  however,  the  rope  winds  perfectly.  The 
sheave  hub  is  lined  with  brasses  about  Y±  in.  thick  and  lubrication  is  had 
by  means  of  two  grease  cup's  in  the  middle  of  the  hub,  diametrically 
opposite.  The  shaft  is  5  in.  in  diameter  and  is  held  in  the  castings  which 
rest  on  the  concrete  piers,  by  means  of  setscrews. 

Derrick  for  Sinking  557  Feet.— Shaft  No.  6  of  the  St.  Louis  Smelting 
&  Refining  Co.  in  southeastern  Missouri  was  sunk  to  a  depth  of  557  ft. 
with  a  boom  derrick.  The  derrick  is  rather  generally  used  in  Missouri 
and  Michigan  for  starting  sinking  operations,  but  100  ft.  has  usually  been 
the  limit  of  depth  to  which  it  is  applied.  Considerations  of  cost  and  con- 
venience led  to  its  adoption  in  this  instance. 


288 


DETAILS  OF  PRACTICAL  MINING 


The  derrick  was  set  opposite  the  center  of  the  long  side  of  the  shaft 
and  38  ft.  back  from  the  center  line.  It  was  steadied  by  six  guy  lines. 
The  mast  was  40  ft.  in  height  and  the  boom  44  ft.  An  elevation  of  the 
derrick  is  shown  in  Fig.  230,  and  a  plan  of  the  whole  layout.  The  bottom 
of  the  mast  was  carried  by  the  footstep  casting  shown,  to  which  it  was 


,G 'Pi am.  Sheave 


10" Channels  -fo 
support  skip 
track* 


FIG.    229. HOISTING    SHEAVES    REVOLVING    ON    FIXED    SHAFT. 

bolted.  This  footstep  rotated  in  a  bearing  block  made  of  10  X  10-in. 
timbers  bolted  together  as  illustrated,  with  a  hole  in  the  center  fitted  to 
the  footstep  shaft.  The  top  of  the  block  carried  a  4J^-ft.  square  plate 
around  the  center  bearing  hole.  The  block  was  bolted  to  the  frame 
structure  supporting  the  derrick.  Rotation  of  the  derrick  was  ob- 


TIMBER  STRUCTURES 


289 


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290  DETAILS  OF  PRACTICAL  MINING 

tained  through  the  12-ft.  bull  wheel,  the  construction  of  which  is  also 
shown  in  detail.  It  was  built  of  6-in.  channels,  one  forming  the  cir- 
cumference and  the  others  acting  as  braces.  The  wheel  was  attached 
to  the  cast  footstep.  The  circumferential  channel  was  turned  with  the 
ribs  out  to  form  a  trough  for  the  actuating  rope. 

Two  hoists  and  a  winch  were  employed  in  conjunction  with  the 
derrick.  The  winch  was  used  for  rotating  the  bullwheel.  A  small 
wire  rope  was  wrapped  several  times  around  the  bullwheel  and  one 
end  brought  back  as  a  tangent  to  a  point  near  the  winch.  The  other 
end  was  brought  around  to  a  point  near  the  first  end  and  turned  in  the 
same  direction  by  a  block  and  also  brought  near  the  winch.  On  the  12- 
in.  winch  drum  a  hemp  rope  was  used,  to  avoid  bending  a  wire  rope  to  so 
small  a  radius.  This  rope  had  its  ends  attached  to  the  ends  of  the 
wire  rope,  one  attachment  being  brought  through  a  block  and  tackle  for 
taking  up  slack. 

The  main  hoisting  cable  passed  over  a  sheave  on  the  end  of  the 
boom  and  another  on  top  of  the  mast,  down  through  a  5-in.  hole  in  the 
footstep  casting,  over  another  sheave  attached  to  the  supporting  frame- 
work and  thus  to  the  hoist.  By  this  arrangement  the  swinging  of  the 
derrick  did  not  interfere  with  the  operation  of  the  rope.  The  rope  to 
the  auxiliary  hoist  followed  through  a  similar  series  of  sheaves  placed  on 
the  opposite  side  of  the  boom  and  mast.  The  slope  of  the  boom  was 
changed  by  hand  when  necessary,  using  a  block  and  tackle  from  the 
top  of  the  mast  to  a  point  near  the  center  of  the  boom.  But  the  bucket 
usually  operated  in  the  shaft  center  and  for  that  reason  the  slope  of  the 
boom  was  seldom  changed.  The  arrangement  of  the  hoists  is  shown  in 
the  plan.  The  winch  was  near  the  main  hoist  so  that  the  engineer 
had  easy  control  over  both;  each  hoisting  operation  of  course  necessitated 
a  turning  of  the  derrick.  Usually  it  was  not  necessary  to  operate  both 
the  auxiliary  and  main  hoists  at  the  same  time,  but  when  it  was,  a  top- 
man  could  manipulate  the  auxiliary,  as  it  was  used  only  for  material. 
The  main  hoist  had  a  4-ft.  drum  and  15  X  18-in.  cylinders.  The  auxiliary 
had  a  30-in.  drum  and  8  X  10-in.  cylinders.  The  winch  had  a  4  X  4-in. 
engine. 

The  bucket  was  unguided  in  the  shaft,  but  no  difficulty  was  ex- 
perienced from  spinning.  It  was  dumped  in  the  usual  manner  by  the 
rope  and  hook  shown.  An  unusual  piece  of  equipment  was  a  platform 
on  which  the  men  worked  while  timbering,  placing  pipe  or  barring 
down  the  sides.  This  so-called  "butterfly"  was  handled  by  the  main 
hoist,  being  attached  by  four  %-in.  ropes  from  the  main  timbers  of  the 
framework.  It  was  a  great  convenience,  giving  opportunity  for  spread- 
ing out  the  tools  while  working  and  being  capable  of  swinging  to  any 
desired  corner  of  the  shaft. 


TIMBER  STRUCTURES 


291 


Advantages  attendant  on  using  a  derrick  are:  (1)  All  surface  work 
is  done  away  with  near  the  collar  of  the  shaft  and  the  danger  of  objects 
falling  on  the  men  at  the  bottom  is  reduced.  The  men  themselves  were 
unloaded  at  least  35  ft.  from  the  collar.  (2)  There  is  no  structure  near 
the  shaft  collar  to  be  injured  by  flying  rock  while  blasting  the  upper 
sections  of  the  shaft.  (3)  The  derrick  is  cheap  to  erect  and  on  the 
completion  of  any  one  job  is  available  for  another.  (4)  By  the  use  of 
two  hoists,  one  for  men  and  one  for  material,  the  work  of  pipe  and 
timber  erection  is  greatly  facilitated.  (5)  By  rotating,  a  great  deal  of 
lifting  is  avoided  both  in  the  shaft  and  around  the  collar  on  the  surface. 


FIG.    231. ELEVATION   AND    DETAILS    OF    SMALL    FOUR-POST   TIMBER   HEADFRAME. 

Small  Four-post  Headframe  (By  H.  L.  Botsford). — Fig.  231  illustrates 
a  small  timber  headframe.  It  was  designed  for  use  at  an  exploratory 
shaft,  from  which  it  was  desired  to  ship  ore  from  time  to  time  as  the  work 
of  development  progressed.  Where  long  timbers  are  not  obtainable 
or  are  too  expensive,  the  headframe  may  be  built  in  sections,  with 
intermediate  caps,  and  holding-down  bolts  between  the  sections.  Strap- 
bolts  answer  this  purpose  and  cost  less  than  long  rods  running  the  full 
length  of  the  section,  from  cap  to  sill. 

Reversible  Temporary  Headframe  (By  P.  V.  Burgett).— Fig.  232 
shows  a  round-timber  headframe  suitable  for  shaft  sinking  and  develop- 
ment work.  It  is  very  simple  in  construction,  and  can  be  quickly  and 
cheaply  erected.  As  first  designed,  it  consisted  pf  only  the  middle  bent 
A,  the  " rakers"  B,  the  dumping  platform  D,  and  a  4-ft.  sheave  wheel 


292 


DETAILS  OF  PRACTICAL  MINING 


E.  The  permanent  hoisting  engine,  on  the  same  side  of  the  shaft  as  the 
"rakers,"  was  to  be  used  for  hoisting.  Later  it  was  found  that  the  hoist- 
ing plant  could  not  be  built  in  time.  So  the  back  braces  C  and  a  2-ft. 
sheave  wheel  F  were  added  to  the  headframe,  and  a  temporary  hoisting 
engine  and  small  upright  boiler  were  erected  on  the  opposite  side  of  the 
shaft  from  the  permanent  engine.  The  details  of  the  middle  bent  A 
are  shown  in  the  drawing.  The  back  braces  and  "rakers"  have  no  cross- 
pieces  for  braces  except  those  used  to  support  the  sheave  wheel.  The 
shaft  has  three  compartments;  two  5-ft.  skipways  and  a  3-ft.  ladderway. 
During  shaft  sinking  the  middle  compartment  was  used  for  hoisting. 

Tripod  Headframe  (By  G.  E.  Le  Veque). — A  serviceable  tripod  head- 
frame  is  made  of  three  32-ft.  poles,  having  12-in.  butts.  These  are  bolted 
at  the  top,  as  shown  in  Fig.  233,  and  a  sheave  hung  from  the  1-in.  bolt. 
The  bottoms  of  the  poles  are  spread  to  form  a  30-ft.  equilateral  triangle. 
The  hoisting  compartment  is  continued  as  a  6  X  7-ft.  inclosure  by  6  X  6- 


FIG.    232. — PROSPECTING   HEADFRAME    FOR   HOIST   ON   EITHER   SIDE. 

in.  posts  braced  by  2  X  6-in.  stringers,  spiked  to  the  tripod  legs  9  ft. 
below  the  sheave.  Eight  ft.  above  the  shaft  collar  a  landing  and  chute 
are  built  in,  a  space  4  X  4-ft.  being  left  for  the  bucket  and  a  platform 
built  at  one  side  for  the  lander.  The  dumping  device  consists  of  a  chain 
with  a  hook  in  the  free  end,  fastened  to  a  stringer  directly  over  the 
chute.  In  operating,  the  bucket  is  hoisted  to  position  C,  the  chain  is 
hooked  in  the  bail  ring  and  the  cable  slacked,  transferring  the  weight  of 
the  bucket  from  the  cable  to  the  chain  and  bringing  the  bucket  directly 
over  the  chute,  where  it  can  be  dumped  by  overturning  to  position  B. 
The  length  of  the  chain  should  be  adjusted  to  allow  the  bucket  to  rest 
lightly  on  the  chute  when  in  dumping  position  and  prevent  its  turning 
entirely  over  and  dropping  material  into  the  shaft. 

Prospecting  Headframe  with  Automatic  Dump  (By  Charles  Mentzel). 
— A  little  consideration  of  the  stresses  in  a  headframe  and  a  few  minutes 
calculation  will  show  that  a  frame  of  good  design  and  sufficient  strength 
and  stability  for  sinking  purposes  can  be  constructed  at  considerably 


TIMBER  STRUCTURES 


293 


less  cost  than  the  four-post  frame,  cross-braced  on  all  sides,  so  often  found 
over  a  prospecting  shaft.  In  addition,  the  greater  convenience,  decrease 
in  surface  attendance  and  greater  speed  in  handling  buckets,  owing  to  the 
self-dumping  arrangement,  give  the  type  illustrated  in  Fig.  234  a  decided 
advantage.  This  headframe  can  be  used  for  either  vertical  or  inclined 
shafts.  In  the  former,  skids  are  easier  to  place  in  the  shaft  than  are 
guides,  and  they  obviate  the  use  of  the  crosshead,  often  a  source  of  danger. 
Where  the  ground  is  good,  all  the  timber  necessary  is  a  wall  plate  about 
every  8  or  10  ft.  tightly  wedged  to  the  ends  of  the  shaft.  The  skids  are 
spiked  to  the  plates.  Prospecting  shafts  usually  follow  the  ore  and, 


'8  "Sheave 


5x6-  Ladder         ^6x6  Hoisting 

Compartment        Compartment 

FIG.    233. TRIPOD    PROSPECT    HEADFRAME    AND    LANDING    PLATFORM. 

therefore,  are  almost  always  inclined ;  and  generally  the  inclination  varies 
from  time  to  time. 

The  essential  points  entering  into  the  design  of  a  headframe  are  the 
height  of  the  car  used  to,  remove  the  hoisted  muck,  and  the  distance  of  the 
hoist  from  the  shaft.  If  it  is  considered  advisable  to  build  a  frame  with  a 
pocket,  which  will  do  away  with  the  services  of  a  top  man  on  night  shift, 
it  is  calculated  to  hold  about  30  tons  and  to  fit  between  the  front  posts. 

The  construction  of  the  bucket  is  the  next  consideration.  A  bucket 
of  approximately  10  cu.  ft.  capacity  is  usually  about  26  in.  diameter  at 
the  top,  24  in.  at  the  bottom  and  about  34  in.  deep.  Two  horns,  8  or  9 
in.  long  and  1^  in.  in  diameter,  are  fastened  to  opposite  sides  of  the 


294 


DETAILS  OF  PRACTICAL  MINING 


TIMBER  STRUCTURES  295 

bucket  about  9  or  10  in.  from  the  bottom,  as  shown.  They  are  attached 
to  flanges  riveted  inside  and  outside  the  bucket  as  shown  in  detail  below 
the  view  of  the  bucket  itself. 

The  position  of  the  sheave  depends  upon  the  height  of  the  dumping 
device  and  the  amount  of  overwind  allowable.  In  prospecting  shafts 
the  danger  of  overwinding  is  small  with  the  slow,  low-power,  geared 
hoists  usually  employed,  so  5  ft.  is  sufficient,  and  taking  the  length  of  bale, 
clevis,  thimble  and  about  2  ft.  of  cable  doubled  to  clamp  it,  gives  about 
10  or  12  ft.  as  the  distance  from  the  dump  to  the  tangent  point  of  the 
sheave  wheel.  Knowing  the  diameter  of  the  sheave  and  the  size  of  the 
pillow  blocks,  the  vertical  posts  can  be  readily  located.  Having  the 
front  posts,  the  back  braces  may  be  drawn  as  follows:  Scale  off  the 
distance  of  the  hoist  from  the  collar  as  shown  in  the  diagram.  Draw 
AE  tangent  to  hoist  drum  and  sheave.  Theoretically  the  line  AD 
bisecting  the  angle  EAB  is  in  the  best  position  to  receive  the  pull  of  the 
hoist  and  the  resisting  pull  of  the  load.  AD,  however,  may  be  too  close 
to  the  line  of  the  vertical  posts  to  ensure  stability,  and  it  is  better  in  any 
event  to  place  it  so  that  the  foot  comes  closer  to  the  hoist  at  F.  The 
positions  of  the  posts  and  back  braces  have  now  been  decided.  To  find 
out  how  to  place  these  with  respect  to  the  shaft  we  must  consider  how 
the  bucket  rides  on  the  skids.  This  is  shown  in  the  plan  of  the  shaft, 
and  in  the  elevation  of  the  headframe  and  at  A.  The  skids  are  6-  or 
8-in.  round  skinned  poles  dressed  at  the  parts  where  they  are  fastened  to 
the  wall  plates  and  are  placed  so  that  the  bucket  rides  on  them  as  shown, 
without  touching  the  wall  plates.  The  horns  do  not  come  into  contact 
with  anything  in  the  shaft.  With  this  sketch  made  we  have  the  position 
of  the  hoisting  cable  with  respect  to  the  shaft  and  headframe,  and  can 
locate  the  posts  and  back  braces. 

The  posts  are  tied  with  three  girts  and  a  cap,  and  the  back  braces 
with  two  girts.  The  batter  may  be  1:8  or  1:10,  depending  on  the  size 
of  the  shaft.  For  a  foundation,  ordinary  log  cribwork  is  built  up  and 
filled  with  waste  rock  and  the  stringers  spiked  to  the  cribbing  with  drift 
bolts.  In  one  frame  10  X  10-in.  hewed  timber  was  used  and  1-in.  tie 
rods  and  bolts,  and  8  X  8-in.  timber  for  the  bin.  A  smaller  frame  was  con- 
structed of  8  X  8-in.  timber  and  %-in.  tie  rods.  The  front  posts  are  set 
at  the  inclination  of  the  shaft  and  are  connected  with  the  back  braces 
by  means  of  girts  and  tie  rods. 

The  shaft  skids  run  from  the  shaft  to  the  point  of  dump.  The 
dumping  skids  of  8  X  8-in.  timber  begin  about  6  ft.  below  the  dump  and 
are  bolted  to  the  headframe.  As  the  bucket  is  hoisted  out  of  the  shaft, 
the  horns  ride  on  the  runners  on  the  dumping  skids,  which  are  placed 
so  that  the  distance  between  the  inner  faces  is  an  inch  or  two  greater  than 
the  width  of  the  bucket,  to  allow  clearance.  The  shaft  skids  prevent 


296 


DETAILS  OF  PRACTICAL  MINING 


the  bucket  from  tipping  on  the  horns  at  this  point.  The  bucket  continues 
up  the  dumping  skids  until  the  horns  drop  into  a  dap  on  each  skid.  At 
this  point  the  hoist  is  stopped  and  the  bucket  allowed  to  swing  by  gravity, 
thus  dumping.  The  bucket  is  now  raised  a  foot  or  so  and  then  lowered. 
In  lowering,  the  horns  engage  trippers  which  are  thrown  over  the  daps, 
allowing  the  horns  to  slide  down  without  catching  in  the  daps.  The 
trippers  then  swing  back  by  gravity  leaving  the  daps  free  to  hold  the 
horns  of  the  bucket  on  the  next  trip. 

The  dumping  device  is  simple  and  can  be  made  by  any  mine  black- 
smith. The  construction  is  shown  on  the  right  of  Fig.  234.  The  tripper 
E  is  shown  in  full  lines  in  its  normal  position.  When  the  horn  B  engages 
it  on  its  down  trip  it  carries  it  with  it  until  it  is  stopped  by  the  catch  D. 
This  enables  the  horn  to  go  past  the  dap  C  without  being  stopped  by  it, 
as  shown  by  the  dotted  lines.  After  the  bucket  has  passed,  the  tripper 
swings  back  to  its  first  position  by  gravity,  since  the  lower  part  of  the 


Chain  and 
hook  for 
swinging 
out  bucket 


FIG.    235. HOISTING    ARRANGEMENT   FOR   PROSPECT   SHAFT. 

tripper  is  made  heavier  than  the  upper.  The  runner  A  with  the  dap  C, 
which  should  be  at  least  2  in.  deep,  is  made  of  %  X  2-in.  iron  bolted  flush 
with  the  timber.  The  tripper  is  best  made  of  %  X  3-in.  iron  and  about 
20  in.  long  and  should  swing  from  a  1-in.  bolt.  The  construction  is  ap- 
parent. A  headframe  of  this  description  can  be  built  at  a  cost  of  about 
$50  for  a  small  one  and  $150  for  a  larger  one,  including  all  material  and 
labor.  Any  carpenter  of  ordinary  ingenuity  should  have  no  trouble  in 
designing  and  framing  it.  For  vertical  shafts  the  same  form  can  be  used, 
carrying  the  skids  up  and  bending  them  at  the  collar  to  meet  the  frame 
at  the  dump.  A  few  saw  cuts  on  the  inside  of  a  green  pole  make  it 
possible  to  bend  it  through  a  considerable  angle  without  breaking.  Of 
course,  a  roller  for  the  cable  is  required  at  the  shaft  collar  in  this  case. 
Substitute  for  Small  Headframe  (By  Walter  R.  Hodge).— The  type 
of  head  rigging  shown  in  Fig.  235  has  been  used  in  many  places  on  the 
Mesabi  range  in  sinking  test  pits  and  shallow  timber  shafts.  It  would 
be  useful  in  most  places  where  a  temporary  headframe  is  needed  for 


TIMBER  STRUCTURES  297 

shallow  depths.  It  consists  of  two  pieces  of  round  timber  about  28  ft. 
long,  supported  a  little  more  than  half  way  toward  the  small  end  by  a 
roughly  made  bent  slightly  inclined.  The  large  end  is  weighted  with 
waste  rock  or  timber.  The  two  timbers  are  set  close  together  and  the 
sheave  revolves  between  them.  The  sheave  is  retained  in  place  by  two 
collars  or  simply  revolves  between  two  heavy  pegs  driven  in  the  logs. 
Such  a  device  may  do  good  work  to  a  depth  of  200  ft.  A  small  "puffer" 
is  usually  the  source  of  power  on  the  Mesabi.  A  windlass  may  be 
framed  to  the  butts  of  the  timbers  and  leave  the  collar  of  the  shaft  free 
from  obstructions. 

TURN  SHEAVES 

Turn-sheave  Types  (By  Floyd  L.  Burr). — In  any  turn-sheave  frame 
whatever,  the  sheave  wheel  will  be  supported  by  a  pair  of  members 
whose  axes  lie  in  planes  parallel  to  the  plane  of  the  sheave.  Generally 
also  the  plane  containing  these  two  axes  will  be  at  right  angles  to  the 
plane  of  the  sheave.  These  members  will  usually  at  their  ends  frame  into 
main  supports  which  are  vertical,  horizontal  or  at  right  angles  to  the 
sheave  supports.  Four  types  of  turn-sheave  or  angle-sheave  frame  may 
be  recognized. 

Type  No.  1. — When  the  line  of  the  resultant  of  the  two  ropes  is  steep 
and  either  upward  or  downward,  the  principal  part  of  the  frame  may 
take  the  form  of  a  pair  of  members  parallel  to  the  resultant  reaching 
upward  into  the  air  from  a  concrete  or  other  base.  The  sheave  is  at- 
tached to  these  members  and  the  stress,  tension  or  compression  depending 
upon  the  direction  of  the  resultant,  is  transmitted  to  the  concrete  base, 
which  by  virtue  of  its  weight  resists  the  lifting  tendency  or  by  its  stiffness 
spreads  the  compression  over  a  sufficient  area  of  the  soil  beneath,  while 
by  end  bearing  and  skin  friction  it  resists  the  tendency  to  slide  hori- 
zontally. The  tension  or  compression  members  may  be  of  steel  or  wood. 

Type  No.  2. — When  the  line  of  the  resultant  is  comparatively  flat, 
the  frame  may  consist  essentially  of  a  pair  of  strut-beam  members  parallel 
to  the  resultant,  framed  between  two  piers  or  towers,  one  or  both  of 
which  will  tend  to  overturn  in  a  longitudinal  direction  when  the  rope  is 
stressed.  The  piers  or  towers  may  be  of  steel  or  wood  or  concrete  or 
reinforced  concrete,  while  the  strut-beam  may  be  of  wood,  steel  or  rein- 
forced concrete.  The  towers  or  piers  may,  as  a  variation  in  design,  get 
some  of  their  stability  from  diagonal  tension  or  compression  braces 
reaching  to  the  ground  or  to  auxiliary  piers  or  natural  anchorages. 

Type  No.  3. — The  same  sort  of  a  structure  as  that  mentioned  for  type 
2  may  be  set  with  the  supporting-beam  members  normal  to  the  resultant. 
In  this  case  the  resultant  load  subjects  the  members  to  the  bending  stress 
only,  and  tends  to  overturn  the  towers  in  a  transverse  direction. 


298 


DETAILS  OF  PRACTICAL  MINING 


Type  No.  4. — When  it  is  not  convenient  to  set  the  supporting  members 
either  parallel  or  normal  to  the  line  of  the  resultant,  these  members  may 
be  set  in  a  convenient  direction  and  supported  by  two  towers  or  piers. 
The  stress  effects  are  of  course  a  combination  of  those  in  the  preceding 
two  types. 

It  should  also  be  mentioned  that  in  the  last  three  types  there  may  be 
only  one  heavy  pier  or  tower,  from  which  beams  may  extend  as  cantilevers 
to  support  the  sheave  wheel.  Of  course,  many  variations  are  possible. 

Fig.  236  shows  sketches  of  these  various  types. 

An  installation  at  "C"  shaft  of  the  West  Vulcan  mine,  of  the  Penn 
Iron  Mining  Co.,  Vulcan,  Mich.,  gives  an  illustration  of  types  1  and  2. 
The  hoisting  ropes  emerging  from  the  hoist  house  travel  about  80  yd. 
toward  the  east,  thence  a  similar  distance  to  the  north  to  a  point  near 


Vbod&eel  or  reinforced 
Fesuttairt-  concrete  members 

'  '     '  "'      '     'Concrete  Pier  I 


Elevation 


!   » 


Plan 

TYPE/* > 


- TYPE   1 J       k" TYPE  Z- 

FIG.    236. THE   FOUR  TYPES   OF   ANGLE-SHEAVE     FRAMES- 

the  base  of  the  headframe  and  thence  in  a  westerly  direction  to  the 
headsheaves.  In  their  travel  to  the  east  and  north,  the  ropes  run  ex- 
tremely flat,  while  in  rising  to  the  west  toward  the  headsheaves  they  are 
steep.  The  conditions  thus  called  for  a  type-2  frame  for  the  first  turn, 
that  nearest  the  hoist,  and  a  type-1  frame  for  the  second.  These  new 
frames  were  to  replace  old  decayed  wooden  structures  and  had  to  be  built 
and  made  ready  for  use  before  disturbing  the  old  ones.  It  was  also  neces- 
sary so  to  arrange  that  there  should  be  no  interference  with  the  run  of  the 
ropes  into  the  old  structures  and  in  the  case  of  the  type-2  new  structure 
these  ropes  had  to  run  through  the  frame — indeed,  through  holes  cored  in 
one  of  the  concrete  piers.  The  general  relations  are  shown  in  plan  and 
profile  in  Fig.  237. 

Type-1  structure  consists  of  a  concrete  base  with  its  top  flush  with  the 
ground  surface,  from  which  emerge  three  steel  frames  on  a  slant.  Each 
frame  is  to  support  a  sheave,  one  each  for  the  cage,  the  skip,  and  the  skip 
balance.  A  separate  structure  will  be  built  in  case  the  future  demands  a 
cage  balance.  Each  frame  consists  of  a  pair  of  steel  members  cross- 
braced  together  rigidly  below  the  open  space  occupied  by  the  sheave  and 


TIMBER  STRUCTURES 


299 


300  DETAILS  OF  PRACTICAL  MINING 

provided  with  crosspieces  at  the  lower  end  for  anchorage  into  the  con- 
crete. The  concrete  base  slab  is  about  7  ft.  deep;  the  steel  members 
reach  nearly  to  the  bottom  and  extend  above  the  concrete  to  a  point 
just  above  the  bearings  of  the  sheave  wheel.  The  balance-rope  sheave 
will  be  6  ft.  in  diameter;  the  others  are  10  ft.  The  intersection  points  were 
placed  about  flush  with  the  ground  level.  Each  member  is  made  up  of 
an  I-beam  with  a  channel  riveted  to  its  upper  flange,  giving  stiffness  in 
two  planes.  The  bearings  for  the  sheave  rest  upon  the  upper  flange,  or 
channel  web,  and  are  attached  by  bolts  which  reach  through  the  bottom 
flange.  Angle-steel  braces  are  attached  to  these  members  near  their 
upper  ends  and  reaching  down  to  auxiliary  anchorage  piers  help  to  stay 
the  main  members  against  the  bending  stresses  which  occur  by  reason 
of  the  eccentricity  of  the  position  of  the  center  of  the  sheave.  This 
placing  of  the  bearings  on  one  flange  of  the  members  is  not  a  thoroughly 
satisfactory  detail  and  in  future  installations  an  attempt  at  improvement 
will  be  made.  The  center  of  the  sheave  and  the  resultant  should  coincide 
with  the  plane  of  the  center  lines  of  the  members,  and  thus  do  away  with- 
practically  all  bending  moment. 

The  concrete  base  being  all  below  the  ground  level,  the  placing  of  the 
concrete  was  exceedingly  simple.  The  mixer  was  set  up  at  one  edge  of 
the  excavation  and  after  the  steel  members  had  been  placed  in  proper 
position  the  concrete  was  merely  poured  direct  from  the  mixer  into  the 
forms — the  excavation  was  in  an  old  rock  fill  and  would  not  stand  without 
form  work.  About  75  cu.  yd.  of  concrete  was  consumed.  Considerable 
irregular  reinforcement  was  placed  in  the  concrete  with  the  idea  of  bind- 
ing it  together  to  act  as  one  mass  and  suspend  it  from  the  steel-work. 
This  reinforcement  consisted  of  old  steel  rope  1J^  in.  or  1%  in.  in  size. 
A  force  of  nine  men  spent  one  and  one-half  days  at  the  work  of  actual 
concreting. 

The  ropes  approaching  these  sheave  wheels  from  a  lower  elevation 
had  to  run  under  the  surface  of  the  ground  for  about  35  ft.  from  their 
intersection  with  the  slope  of  the  hill.  The  elevation  of  the  intersection 
points  was  purposely  fixed  so  that  the  ropes  would  enter  below  the  surface 
in  order  to  pass  under  the  rock  and  ore  tramway  tracks.  It  was  not 
practicable  to  build  concrete  tunnels  or  conduits  for  the  ropes  on  account 
of  their  position  about  15  ft.  above  and  directly  over  an  old  tunnel 
through  which  the  old  ropes  entered  the  deep  pit  containing  the  old 
angle  sheaves.  Therefore  it  was  decided  to  let  the  ropes  run  each  through 
a  sleeve  or  conduit  consisting  of  a  length  of  old  discarded  36-in.  steel 
stack.  These  pieces  of  stack  were  suspended  from  stringers  spanning 
the  old  tunnel  and  uncertain  ground.  After  the  ropes  were  put  into 
operation  in  the  new  sheaves,  the  old  pit  and  tunnel  were  filled  with 
waste  mine-rock  up  to  and  over  the  conduits.  The  extreme  depth  of 


TIMBER  STRUCTURES  301 

the  ropes  below  the  surface  is  about  4  or  5  ft.  at  the  edge  of  the  bank 
and  of  course  at  the  point  of  entering  the  sheave  is  nothing. 

Type-2  structure  shown  in  Fig.  238a  consists  of  a  concrete  base  12  ft. 
wide,  25  ft.  long,  and  5  ft.  deep,  surmounted  by  two  concrete  piers  16 
ft.  high  by  8  ft.  wide  by  5  ft.  long.  The  top  of  the  base  is  flush  with  the 
general  ground  surface.  The  piers  are  placed  symmetrically  with  the 
center  lines  of  the  base  and  there  is  12j^  ft.  clear  space  between  them. 
The  long  center  line  coincides  approximately  with  the  lines  of  the  re- 
sultants and  lies  in  a  northwest-southeast  direction.  Thus  there  are 
the  "northwest  pier"  and  the  "southeast  pier."  The  sheaves,  which 
are  10  and  6  ft.  in  diameter,  are  supported  by  pairs  of  steel  members 
located  one  above  another  and  spanning  the  distance  between  the  two 
piers.  Provision  has  been  made  for  four  sheaves  though  there  are  now 
only  the  two  main  sheaves  installed.  The  supports  for  the  6-ft.  sheaves 
are  only  partially  installed  and  will  be  completed  whenever  needed. 
Tension  in  the  ropes  produces  compression  in  the  steel  members  which 
push  against  the  northwest  pier,  tending  to  bend  and  break  it,  to  tear 
it  off  from  the  base  and  to  tip  the  whole  structure,  base  and  all,  over 
toward  the  northwest. 

The  situation  of  this  structure  bears  such  a  relation  to  the  mine 
workings  below  that  there  is  a  possibility  of  some  settlement.  For  this 
reason  it  was  considered  necessary  to  build  so  that  the  steel  members 
could  upon  occasion  be  removed,  rearranged,  and  put  back,  in  case 
settlement  should  occur  so  as  to  affect  the  sheaves  more  than  could 
be  adjusted  for  by  blocking  up  their  bearings.  To  accomplish  this  pur- 
pose, the  steel  members  are  not  embedded  into  the  two  piers  but  merely 
butt  against  them.  They  are  attached  to  the  piers  in  such  a  way  as 
to  have  their  dead  weight  and  that  of  the  sheaves  supported.  A  small 
space  is  allowed  for  the  expansion  of  the  steel  so  as  not  to  put  a  com- 
pressive  stress  therein  nor  to  put  an  additional  overturning  moment  or 
spreading  force  on  the  piers. 

The  northwest  pier  is  calculated  as  a  cantilever  from  the  base  slab 
to  resist  safely  the  stressing  effects  of  the  breaking  of  the  upper  rope 
while  the  other  three  ropes  are  carrying  their  working  load.  The  hoist- 
ing ropes  in  use  are  1  J£  in.,  but  1^-in.  ropes  were  assumed  in  the  compu- 
tations. The  balance  ropes  were  assumed  to  be  %  in.  The  base  slab 
was  reinforced  top  and  bottom  to  insure  its  acting  as  one  piece.  The 
northwest  pier  was  reinforced  as  a  cantilever,  the  reinforcement  being 
continuous  with  that  in  the  base.  This  reinforcement  consists  of  dis- 
carded IJ^-in.  and  IJ^-in.  steel  ropes.  These  ropes  were  used  rather 
lavishly.  It  was  found  convenient  to  let  them  run  up  into  the  southeast 
pier  much  as  in  the  northwest  pier,  so  that  it  is  actually  reinforced,  though 
there  is  no  definite  requirement  for  such  reinforcement.  The  function 


302 


DETAILS  OF  PRACTICAL  MINING 


a 

P 

Si-:-:>:-:-::-.-.'- 
S^v.:-.:^- 

'&$$•&  ', 

fK& 

iSft; 

R 

|S 

n 
SB 

1 

11 

ii 

TV,  jT 

T*r,  ,'1^' 

1 

.  1  t 

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I 

1 

<  -^ 

c\  ^ 

\ 
^ 

*     * 

I  11  tl  ill  ill 


H 

I    I 
J    g 

!  3 


ptpi  k- ^/ 


TIMBER  STRUCTURES  303 

of  this  southeast  pier  is  to  furnish  weight  for  stability  of  the  whole  struc- 
ture and  to  support  the  dead  weight  of  the  steel  frames  and  their  sheaves. 
It  also  serves  to  resist  its  share  of  any  incidental  lateral  stresses. 

The  pit  for  the  base  having  been  excavated  and  forms  for  the  piers 
erected,  a  number  of  long  ropes  were  laid  in  a  longitudinal  direction  in 
the  bottom,  then  about  18  in.  of  concrete  was  placed,  embedding  the 
ropes  about  2  or  3  in.  from  the  bottom.  Also  at  each  end,  there  were 
embedded  certain  anchorages  made  of  old  rails.  These  supported  hori- 
zontal rails  at  the  inside  points  of  junction  between  the  piers  and  the 
base.  They  were  to  serve  a  little  later  to  take  the  strain  arising  from 
tightening  the  inside  face  ropes.  The  ends  of  the  long  ropes,  the  middle 
portions  of  which  were  now  embedded  in  the  18  in.  of  concrete,  were 
picked  up  and  some  of  them  drawn  up  tight  into  the  pier  forms  near 
their  outside  faces.  Their  upper  ends  were  wired  to  strong  wooden 
beams  which  had  been  supported  by  bents  over  the  forms.  The  rest  of 
these  ends  were  laid  back  on  top  of  the  18  in.  of  the  concrete,  to  be 
embedded  into  the  bottom  of  the  remaining  3}/£  ft.  of  base.  It  should 
be  mentioned  that  in  casting  this  18  in.  of  base,  scrap  rails  and  rods  were 
embedded  vertically  here  and  there  to  bond  to  it  the  remaining  portion 
of  the  base. 

The  other  series  of  ropes  was  now  put  in  place.  These  followed  down 
the  inside  face  of  one  pier  form,  then  behind  the  anchorage  bar  men- 
tioned above,  thence  horizontally  across  the  intervening  12J^  ft.  to  the 
other  pier  at  an  elevation  a  few  inches  below  the  top  surface  of  the  base 
slab,  thence  behind  similar  anchorage  bars  and  up  into  the  other  pier 
form  near  its  inner  face.  This  latter  series  is  of  the  greatest  impor- 
tance, since  it  provides  the  cantilever  reinforcement  of  the  northwest 
pier.  The  ends  of  these  ropes  were  wired  to  overhead  wooden  beams 
after  the  ropes  had  been  well  tightened  by  use  of  the  tackle.  Concrete 
was  then  poured  to  complete  the  base  and  the  piers.  The  pier  forms 
were  of  rough  planks  but  were  lined  with  tarred  felt  both  as  a  non- 
freezing  precaution  and  to  make  the  forms  watertight.  Concrete  was 
mixed  in  proportions  varying  from  1 : 2  :  4  to  1:3:5. 

The  concreting  plant  consisted  of  a  No.  11  Cube  mixer  with  loading 
skip,  stockpiles  of  sand  and  rock  on  the  ground  in  the  immediate  vicinity, 
a  36-ft.  wooden  elevator  tower  containing  a  self-dumping  bucket  into 
which  the  mixer  would  discharge  directly,  an  inclined  wooden  trough  or 
chute  with  branches  above  the  forms,  and  an  electric  hoist  for  operating 
the  bucket  elevator.  This  plant  worked  smoothly.  A  force  of  10  men 
was  required  to  mix  and  place  the  concrete.  One  full  and  two  frac- 
tional days  were  consumed  in  the  concreting.  The  concrete  amounted 
to  104  cu.  yd. 

An  example  of  a  type-4  structure  is  furnished  by  a  design  now  in 


304  DETAILS  OF  PRACTICAL  MINING 

process  of  erection  at  East  Vulcan  No.  4  shaft,  shown  in  Fig.  238.  This 
is  to  carry  two  8-ft.  sheaves  for  the  cage  and  skip  ropes.  The  horizontal 
angle  between  the  ropes  lacking  only  8°  or  10°  of  180°,  the  intensity  of 
the  resultant  stress  is  comparatively  slight.  The  structure  is  designed 
to  be  stable  and  strong,  to  withstand  the  effect  of  breaking  one  1^-in. 
rope  while  the  other  rope  is  carrying  its  working  load. 

This  frame  consists  of  a  concrete  base  2  ft.  6  in.  thick  and  10  X  16 
ft.  horizontal  dimensions,  surmounted  at  each  end  by  piers  2  ft.  9  in. 
long  and  5  ft.  wide.  The  north  pier  is  11  ft.  6  in.  high,  while  the  south 
pier  is  10  ft.  high.  Framed  between  the  piers  and  cast  integrally  with  them 
are  reinforced-concrete  beams  which  are  to  support  the  weight  of  the 
sheaves  (a  vertical  load)  and  resist  the  lateral  force  of  the  rope-stress 
resultant.  The  resultant  tends  to  bend  them  toward  the  east  and  through 
the  medium  of  these  beams  to  overturn  the  piers  and  indeed  the  whole 
structure  in  the  same  direction.  There  is  also  a  small  end  thrust  exerted. 
Old  steel  ropes  are  placed  as  reinforcement  to  cause  the  base  to  act  as 
one  piece  and  to  bind  the  piers  firmly  to  it.  The  concrete  is  a  rubble 
mixture  1:3:5.  About  31  cu.  yd.  is  required. 

Certain  conditions  not  necessary  to  mention,  fixed  the  position  of 
the  structure  and  limited  the  width  of  the  piers.  The  structure  is  set 
with  its  transverse  center  line  at  angles  of  some  5°  or  10°  from  the  lines 
of  resultant  of  the  cage  and  the  skip  ropes.  For  the  exact  setting  of  the 
beam  forms,  a  mechanical  scheme  was  used.  This  worked  nicely  for 
this  case  but  would  not  be  convenient  for  use  in  general. 

The  intersection  points,  which  are  on  the  west  side  of  the  structure, 
were  located  and  marked  in  space  by  the  heads  of  nails  driven  into  suitable 
wooden  falsework.  It  was  possible  to  see  easily  from  these  points  to 
points  where  the  ropes  would  enter  the  headsheaves  and  to  the  drums. 
Other  nails  were  sighted  in  along  these  lines  at  distances  of  15  ft.  or  so  from 
the  intersection  points.  A  suitable  wire  was  stretched  along  these  lines, 
which  were,  of  course,  the  future  paths  of  the  ropes.  Then  on  the  east 
side  of  the  structure,  the  transit  was  "jiggled"  into  line  between  the  same 
points  at  headsheave  and  drum  and  lines  were  stretched  to  correspond. 
Thus  for  each  sheave  wheel  there  were  had  three  lines  which  determined 
the  plane  of  the  sheave.  Now  by  sighting  across  these  lines  from  east  to 
west,  strips  were  accurately  located  and  aligned  on  the  pier  forms  for 
the  support  of  the  beam  forms.  The  longitudinal  slope  of  the  beams 
is  about  17°  for  the  cage  sheave  and  15°  for  the  skip,  while  the  transverse 
slopes  are  about  14°  and  3°  respectively. 

The  best  material  for  beams  for  structures  of  types  2,  3  or  4  is  rein- 
forced concrete,  since  it  can  be  so  easily  molded  to  any  desired  detail 
for  support  of  sheave  bearings  and  can  be  used  equally  as  well  for  strut- 
beams  as  for  beams  subjected  to  bending  only.  It  is  also  probably 


TIMBER  STRUCTURES 


305 


more  economical   than   steel  when   used   in  connection  with  concrete 
piers. 

Turn-sheave  Location  and  Support  (By  C.  R.  Forbes). — At  a  Lake 
Superior  copper  mine,  a  turn  sheave  was  necessary  because  a  suitable 
place  for  the  hoisting  engine  could  not  be  obtained  in  the  line  of  the 
shaft,  at  a  sufficient  distance  from  the  headsheave  to  permit  the  rope  to 
wind  properly  on  the  drum  of  11-ft.  face;  a  minimum  distance  of  400  ft. 
was  required  and  at  that  distance  there  was  situated  an  office  building 
and  boarding  house;  furthermore  the  character  of  the  ground  at  this 
point  was  not  suitable  for  constructing  a  hoisting-engine  foundation  at  a 
reasonable  cost.  However,  at  a  point  to  the  east  of  the  shaft,  a  sufficient 


..D.IA9KAM  OF  TURN  SHEAVE 
FIG.    239. — TURN   SHEAVE   LOCATING   FRAME    AND    GUIDING    DIAGRAM. 

distance  away,  there  was  an  outcrop  of  trap  rock  which  made  an  ideal 
place  for  the  foundation,  but  which  necessitated  the  use  of  a  turn  sheave 
shown  in  the  illustrations.  The  method  of  supporting  this  sheave  was 
somewhat  out  of  the  ordinary,  as  the  top  of  the  concrete  base  was  made 
parallel  to  the  plane  of  the  sheave  instead  of  horizontal,  as  is  the  more 
common  practice.  The  timbers  supporting  the  sheave  are  14  in.  square 
and  are  held  in  place  by  1^-in.  bolts  set  in  the  concrete. 

In  constructing  a  foundation  of  this  kind,  the  most  difficult  part  is 
in  locating  and  erecting  the  form  for  the  odd-shaped  concrete  base.  The 
operation  in  this  case  was  accomplished  as  follows.  A  rectangular  frame, 
as  shown  in  Fig.  239,  was  constructed  of  2  X  4-in.  timber,  the  frame 
being  made  the  same  size  as  the  top  of  the  concrete  base.  Projecting 
up  from  this  frame,  perpendicular  to  it,  were  three  upright  pieces;  the 
20 


306  DETAILS  OF  PRACTICAL  MINING 

length  of  these  pieces  was  the  same  as  the  distance  from  the  center  of 
the  sheave  to  top  of  the  concrete,  which  was  determined  by  the  size  of 
the  timbers,  the  length  of  the  hub  and  shaft  of  the  sheave,  etc.  It  was 
necessary  to  use  these  projecting  pieces  to  line  in  the  frame,  as  all  calcula- 
tions were  made  with  respect  to  the  plane  of  the  sheave  itself  and  not  the 
top  of  the  concrete. 

From  a  survey,  the  horizontal  angle  between  the  ropes  was  deter- 
mined and  also  the  slope  of  the  rope  in  each  direction;  and  by  various 
calculations,  the  direction,  the  length  and  the  slope  of  the  line  from  the 
point  of  intersection  of  the  ropes  to  the  center  of  the  sheave,  were  ob- 
tained. To  locate  the  frame,  the  transit  was  set  up  in  the  determined 
line,  and  the  frame  lined  in  by  sighting  along  the  tops  of  the  uprights;  by 
measuring  to  a  plumb  line  suspended  from  the  top  of  the  middle  upright, 
it  was  centered  correctly  and  placed  at  the  proper  height.  The  slope 
in  both  directions  had  been  calculated,  and  by  the  use  of  2°  levels 
set  at  the  proper  angles  and  placed  on  the  frame,  it  was  possible  to  set 
it  at  the  correct  slope,  where  it  was  braced  and  held  firmly  in  posi- 
tion. The  form  was  then  built  around  it  with  a  batter  of  1:4,  and  the 
bolts  set  in  position  and  held  by  a  template  until  the  work  of  filling  in 
with  concrete  was  completed.  It  is  possible  to  locate  a  sheave  of  this 
kind  without  the  use  of  a  transit  by  simply  stretching  chalk  lines  from 
the  point  of  intersection  toward  the  headsheave  and  engine  drum  and 
lining  in  the  sheave  by  eye,  although  this  method  would  not  be  so  ac- 
curate as  the  one  described  and  would  take  more  time  on  the  part  of  the 
workmen. 

The  solution  of  the  turn-sheave  problem,  although  tedious,  is  com- 
paratively simple  and  may  be  accomplished  in  several  ways,  probably 
the  easiest  of  which,  and  one  that  involves  the  use  of  plane  trigo- 
nometry only,  illustrated  in  Fig.  239,  is  as  follows:  From  the  survey, 
the  horizontal  angle  C"  A  B'  between  the  lines  of  rope  is  found  to  be  106°; 
the  slope  of  the  rope  from  the  point  of  intersection  to  the  headsheave, 
46°;  the  slope  of  the  rope  from  the  point  of  intersection  to  the  engine 
drum,  10°;  diameter  of  the  turn  sheave  is  11  ft.  Referring  to  the  dia- 
gram, it  is  readily  seen  how  the  true  angle  between  the  ropes,  the  angle 
CAB,  can  be  determined.  This  angle  is  found  to  be  93°  32',  and  the  line 
from  the  point  of  intersection  A,  to  the  center  of  the  sheave,  will  bisect 
this  angle,  but  it  must  be  remembered  that  the  projection  of  this  line 
on  the  horizontal  plane,  the  line  A0f  in  figure,  will  not  bisect  the  angle 
C'AB'j  and  further  calculations  must  be  made  to  determine  the  hori- 
zontal angle  O'AG'.  It  is  next  necessary  to  determine  the  length  and 
slope  of  the  line  A0\  with  the  data  given  in  the  problem  this  length  is 
found  to  be  7.55  ft.  and  the  slope  40°  41'.  In  order  to  find  the  angle 
O'AG',  draw  OG,  a  horizontal  line  in  the  plane  of  the  sheave.  The  length 


TIMBER  STRUCTURES  307 

of  this  line  can  be  determined,  and  as  it  is  equal  to  O'G',  it  can  be  used  in 
solving  the  triangle  O'AG',  of  which  three  sides  will  be  known;  this  angle 
is  found  to  be  65°  49'. 

The  data  necessary  for  locating  the  sheave  then  are:  Horizontal 
angle  to  be  turned  at  point  of  intersection  from  line  of  rope  to  headsheave, 
65°  49';  horizontal  distance  from  point  of  intersection  to  center  of  turn 
sheave,  5.72  ft.;  vertical  distance  from  point  of  intersection  to  center 
of  turn  sheave,  4.92  ft.;  slope  of  line  from  point  of  intersection  to  center 
of  turn  sheave,  40°  41';  slope  of  line  at  right  angle  to  previous  line  (CB 
in  figure),  22°. 

Turn  Sheaves  at  the  Lake  Mine  (By  Karl  A.  May). — Turn  sheaves 
for  guiding  the  hoisting  ropes  from  the  headframe  sheaves  to  the  hoist 
drums  are  in  use  at  the  Lake  mine,  in  Michigan.  These  serve  the  same 
purpose  as  the  turn  sheaves  described  by  C.  R.  Forbes,  but  differ  in 
design  and  method  of  installation.  The  solution  of  the  problem  of  find- 
ing the  proper  location,  elevation  and  inclination  for  the  sheaves  and 


FIG.  240. MODEL  FOR  SHEAVE  LOCATION. 

frames,  was  essentially  the  same,  but  a  graphic  solution  was  also  made  in 
order  to  check  the  computed  results,  and  in  addition  a  model  was  con- 
structed, the  details  of  which  are  shown  and  explained  by  Fig.  240. 
The  model  was  put  to  good  use  throughout  the  process,  in  overcoming 
some  of  the  difficulties  attendant  on  using  the  third  dimension,  and  in 
laying  out  to  scale  the  existing  conditions  with  a  rather  high  degree  of 
accuracy.  The  sheaves  are  set  at  an  angle  of  about  48°  with  the  hori- 
zontal. Separate  calculations  were  made  for  each  sheave,  although  a 
difference  of  only  about  30'  in  the  angle  of  inclination  resulted. 

When  the  calculations  were  complete,  the  boss  carpenter  was  given 
the  two  center  lines  of  the  foundation,  a  bench  mark,  and  a  print  showing 
the  location  of  the  anchor  bolts,  and  from  these  data  he  built  the  tem- 
plates, which  consisted  of  2-in.  planks,  in  which  holes  were  bored  for 
the  anchor  bolts.  The  planks  were  set  to  bring  the  bolts  at  the  proper 
elevation.  The  latter  were  made  with  the  lower  end  bent  to  a  hook  and 
an  old  20-lb.  rail  was  laid  in  each  line  of  hooks. 


308 


DETAILS  OF  PRACTICAL  MINING 


The  foundation  is  a  level  block  of  concrete  with  right-angled  corners, 
but  set  at  an  angle  of  4°  01'  from  the  line  of  the  rope  to  the  drums,  as  by 
this  means  the  sills  and  the  sheave  frames  are  square  with  each  other  and 
with  the  foundation.  The  sills  and  frames  are  bolted  together  of  12  X  12- 
in.  Oregon  fir  and  tied  with  IJ^-in.  rods.  The  sheaves  are  12  ft.  in  di- 
ameter. The  details  of  the  lower  bearing,  which  is  important,  as  it  takes 
the  greater  part  of  the  load,  are  shown  in  Fig.  241.  Small  guide  pulleys 
are  attached  to  the  frames,  where  the  ropes  enter  and  leave  the  sheaves, 


Adjusting  Screw 


frass  Bushing—** 

L        ^rrfjTmf* 

6'Sherfr  of  Sheave  Wheel-* 


FIG.   241. — LOWER  BEARING   OP   SHEAVE   SHAFT. 

to  take  up  lash  and  prevent  the  ropes  from  jumping  out,  due  to  stretching 
or  to  sudden  stopping  and  starting  of  the  hoist. 


TRESTLES 

Tabulation  of  Trestle  Bent  Dimensions  (By  Clinton  Kimball). — 
The  following  method  of  laying  out  and  dimensioning  the  bents  of  a 
tramway  trestle,  at  one  of  the  mines  in  Wisconsin,  was  used  with  con- 
sequent saving  of  time  in  engineer's  field  work  and  in  carpenter  work. 
The  tramway  described  is  1250  ft.  long  and  constructed  to  carry  a  car 


TIMBER  STRUCTURES 


309 


having  a  gross  weight  of  2  tons.  The  bents,  as  shown  in  Fig.  242,  con- 
sist of  two  4  X  6-in.  inclined  posts  A,  with  a  6  X  6-in.  by  4-ft.  cap  and 
2  X  6-in.  diagonal  braces  C  and  the  tie  pieces  B.  These  bents  are  spaced 
16  ft.  between  centers  and  carry  3  X  12-in.  stringers;  each  post  rests  on 
a  12  X  12-in.  concrete  pier  extending  2  ft.  below  the  soil  surface.  Each 
stringer  is  spliced  over  the  cap  with  two  1  X  12-in.  by  4-ft.  boards  and 
diagonally  braced  at  each  end  to  the  posts  with  2  X  6-in.  by  8-ft. 
pieces.  Bents  over  12  ft.  high  are  connected  by  longitudinal  2  X  6-in. 
tie  pieces  placed  6  to  8  ft.  below  the  stringers.  Stakes  were  driven  on  the 
center  line  of  the  proposed  tramway  and  carefully  spaced  16  ft.  apart  on 
the  horizontal.  A  nail  was  driven  in  each  stake  to  mark  accurately  the 


r— -w— >|«—  W •*>* 

PIG.    242. BENT,    SHOWING    CONSTANT   AND  VARIABLE    DIMENSIONS. 

center  of  each  trestle  bent.  A  profile  of  the  tops  of  these  stakes  indi- 
cating tops  of  piers  was  plotted  from  regular  level  notes.  A  profile 
of  the  grade  of  the  tramway  base  of  the  rail  was  plotted  on  the  same  sheet 
and  the  height  H  from  top  of  piers  to  base  of  rail  was  thus  found.  This 
was  later  checked  by  computation.  Having  the  distance  H  for  each 
bent,  the  dimensions  A,  B,  C  and  W  are  readily  specified,  using  the  ac- 
companying table  and  interpolating.  The  other  pieces  were  of  constant 
dimensions.  It  is  desirable  to  keep  the  tops  of  piers  at  such  a  height 
that  the  pair  supporting  a  bent  shall  have  their  tops  on  the  same  level 
and  that  the  one  on  higher  ground  shall  be  nearly  flush  with  the  soil 
surface. 


310 


DETAILS  OF  PRACTICAL  MINING 


RELATIVE  DIMENSIONS  OF  VARIABLE  MEMBERS  OF  TRESTLE  BENT  FOR 
DIFFERENT  HEIGHTS 


H 

A 

B 

C 

w 

H 

A 

B 

C 

W 

Ft.      in. 

Ft.    in. 

Ft.     in. 

Ft.    in. 

Ft.     in. 

Ft.    in. 

! 

Ft.     in. 

Ft.     in. 

Ft.     in. 

Ft.     in. 

3 

1-  3% 

*| 

3-6 

1-  9% 

13-4 

11-9% 

7-0 

10-0 

3-  6% 

3-4 

1-  7% 

a§ 

4-0 

1-10% 

13-8 

12-  1% 

7-0 

10-0 

3-  6% 

3-8 

1-11}$ 

2L 

4-0 

1-10% 

14 

12-5% 

7-0 

10-0 

3-  7% 

4 

2-  3% 

X'oa 

"*          00 

4-0 

1-11% 

14-4 

12-9% 

7-0 

10-0 

3-  8% 

4-4 

2-  7% 

jU-g'-g 

4-0 

2-0% 

14^8 

13-  1M 

7-0 

10-0 

3-  8% 

4-8 

2-11% 

£5  a 

4-0 

2-  0% 

15 

13-  5% 

7-0 

10-0 

3-  9% 

5 

3-  3% 

4-  6 

4-0 

2-  1% 

15-4 

13-  9% 

7-0 

10-0 

3-10% 

5-4 

3-  7% 

4-  6 

4-0 

2-  2% 

15-8 

14-  1% 

7-0 

10-0 

3-10% 

5-8 

3-11% 

4-  7 

5-0 

2-2% 

16 

14-  5% 

7-0 

10-0 

3-11% 

6 

4-3% 

4-  7 

5-0 

2-  3% 

16-4 

14-  9% 

8-0 

12-0 

4-  0% 

6-4 

4r-7% 

4-  7 

5-0 

2-4% 

16-8 

15-  1% 

8-0 

12-0 

4-  0% 

6-8 

5-  0 

4-  7 

5-0 

2-  4% 

17 

15^-  5% 

8-0 

12-0 

4-  1% 

7 

5-  4 

4-  9 

5-6 

2-  5% 

17-4 

15-  9% 

8-0 

12-0 

4-2% 

7-4 

5-  8% 

4-  9 

5-6 

2-6% 

17-8 

16-  1% 

8-0 

12-0 

4-2% 

7-8 

6-0% 

4-  9 

5-6 

2-6% 

18 

16-  5% 

8-0 

12-0 

3-3% 

8 

&-4K 

4-  9 

5-6 

2-  7% 

18-4 

16-9% 

8-0 

12-0 

4-  4% 

8-4 

6-8% 

4-  9 

5-6 

2-  8% 

18-8 

17-  2 

8-0 

12-0 

4r-    4% 

8^8 

7-0% 

4-  9 

5-6 

2-8% 

19 

17-  6 

8-0 

12-0 

4-5% 

9 

7-4% 

4-11 

6-0 

2-  9% 

19-4 

17-10% 

9-0 

14-0 

4-  6% 

9-4 

7-8% 

4^11 

6-0 

2-10% 

19-8 

18-2% 

9-0 

14-0 

4-  6% 

9-8 

8-0% 

4-11 

6-0 

2-10% 

20 

18-6% 

9-0 

14-0 

4-  7% 

10 

8-  4% 

5-  3 

6-0 

2-11% 

20-4 

18-10K 

9-0 

14-0 

4-  8% 

10-4 

8-8% 

5-  3 

6-0 

3-0% 

20-8 

lfr-2% 

9-0 

14-0 

4-8% 

10-8 

9-  0% 

5-  3 

6-0 

3-  0% 

21 

19-  6% 

9-0 

14-0 

4r-    9% 

•  11 

9-4% 

5-  7 

7-0 

3-  1% 

21-4 

19-10% 

9-0 

14-0 

4-10% 

11-4 

9-8% 

5-  7 

7-0 

3-2% 

21-8 

20-  2% 

b 

4-10% 

11-8 

10-  0% 

5-  7 

7-0 

3-2% 

22 

20-  6% 

1 
jo 

4-11% 

12 

10-  4% 

6-  0 

8-0 

3-  3% 

22-4 

20-10% 

03 

5-0% 

12-4 

10-  8% 

6-  0 

8-0 

3-  4% 

22-8 

21-  2% 

£ 

T3 

5-  0% 

12-8 

11-  1 

6-  0 

8-0 

3-4% 

23 

21-0% 

00 

C 

«*a 

5-  1% 

13 

11-  5 

6-  0 

8-0 

3-  5% 

23-4 

21-10% 

si 

5-2% 

23-8 

22-  2% 

si 

5-  2% 

It  may  be  seen  that  the  framers  were  able  to  proceed  with  the  bents 
independently  of  the  erectors.  The  method  is  recommended  even  for 
tramways  a  few  hundred  feet  in  length  and  especially  in  cases  where  an 
old  tramway  must  be  replaced,  allowing  the  minimum  of  time  for  the 
shutdown  incident  to  replacement,  since  piers  can  be  set  and  all  frame- 
work prepared  to  dimension  before  interfering  with  operations. 

Typical  Coal  Trestles. — The  surface  equipment  of  many  mines  in- 
cludes a  trestle  for  bringing  the  coal  to  a  point  where  it  will  dump  into 
the  boiler-house  bins  and  also  for  providing  storage  against  winter  use. 


TIMBER  STRUCTURES 


311 


The  accompanying  illustrations,  Fig.  243,  show  some  typical  methods 
of  construction  employed  on  the  Mesabi  range  and  also  give  the  profile 
of  one  trestle.  Squared  timber  for  such  trestles  is  almost  universal. 


Number  of 

Length  of 
inside   posts 

Length  of 
outside  post 

Length  of 
sill 

Number 

Length  of 
inside  posts 

Length  of 
outside  post 

Length  of 
sill 

Ft. 

In. 

Ft. 

In. 

Ft. 

In. 

Ft. 

In. 

Ft. 

In. 

Ft. 

In. 

1 

11 

9% 

12 

1% 

16 

0 

12 

17 

10% 

18 

4 

18 

6 

2 

12 

3% 

12 

7y2 

16 

0 

13 

17 

10 

18 

3% 

18 

6 

3 

16 

m 

16 

7% 

18 

0 

14 

17 

9M 

18 

2% 

18 

6 

4 

16 

6% 

16 

11% 

18 

0 

15 

17 

8% 

18 

1% 

18 

6 

5 

16 

10 

17 

3 

18 

0 

16 

17 

7% 

18 

1% 

18 

6 

6 

17 

H 

17 

5% 

18 

0 

17 

17 

7% 

18 

% 

18 

6 

7 

17 

2% 

17 

8 

18 

3 

18 

17 

6% 

17 

11% 

18 

6 

8 

17 

5 

17 

10% 

18 

4 

19 

17 

5% 

17 

10% 

18 

6 

9 

17 

7% 

18 

% 

18 

4 

20 

17 

4% 

17 

10% 

18 

6 

10 

17 

Q1A 

18 

2% 

18 

6 

21 

17 

4% 

17 

9% 

18 

6 

11 

17 

n% 

18 

4% 

18 

6 

In  1  is  shown  a  trestle  built  on  a  16°  curve  with  a  2.5  per  cent,  grade. 
The  trestle  is  350  ft.  long  and  every  third  panel  is  braced  with  3  X  12- 
in.  diagonals  to  form  towers.  The  rails  are  laid  directly  on  stringers 
which  are  themselves  carried  on  corbels  over  the  bents  and  are  spliced 
with  steel  plates  on  the  sides.  The  bents  are  symmetrical  and  running 
boards  are  provided  on  both  sides.  In  2  is  represented  a  trestle  similar 
to  that  of  1.  It  is  un symmetrical,  however,  and  the  running  board  is 
on  one  side  only,  carried  by  an  extension  of  the  cap.  In  this  trestle,  the 
grade  is  4  per  cent.,  except  on  one  portion,  which  has  a  12°  curve,  where 
it  is  3  per  cent.  These  grades  and  curves  represent  the  maximum  per- 
missible in  good  design.  The  bents  are  spaced  15  ft.  9  in.  center  to  cen- 
ter and  every  third  panel  is  diagonally  braced  with  3  X  12-in.  planks. 
The  tension  rod  and  filling  blocks  between  the  stringers  are  inserted  at 
every  bent  on  the  tangents,  while  on  the  curve  an  additional  set  is  used 
between  the  bents. 

A  bent  is  shown  in  3  in  which  the  rails  are  carried  on  crossties,  four 
stringers  being  used  in  this  case.  The  trestle  is  symmetrical,  with  foot- 
boards, on  both  sides;  all  the  posts  are  inclined.  The  bents  are  spaced 
16  ft.,  the  long  ties  8  ft.;  between  the  long  ties  are  25-in.  ties  spaced 
2  ft.  In  this  case  also  every  third  panel  is  diagonally  braced.  In  all 
these  three  types  the  safe  maximum  height  is  22  ft.  The  trestle  in  4  is 
similar  to  that  of  3  in  its  use  of  crossties.  The  bents  are  spaced  12  ft.; 
three  stringers  are  used  under  each  rail.  In  5  a  profile  of  this  trestle  is 


312 


DETAILS  OF  PRACTICAL  MINING 


TIMBER  STRUCTURES 


313 


shown,  indicating  the  grades  and  curves  and  in  the  table  the  dimensions 
for  each  bent  are  specified. 

Post  and  Cap  Joint  for  Dumping-trestle. — The  material  stripped 
from  the  Mesabi  openpits  is  disposed  of  in  great  dumps,  which  are 
built  out  and  up  from  a  single  trestle  extending  the  length  of  the  pro- 
jected dump.  This  trestle  is  of  light  construction,  serving  only  to 
start  operations  and  is  finally  buried  and  left.  The  method  of  con- 
struction is  shown  in  Fig.  244.  The  first  material  stripped  is  dumped  in 


PIG.  244.- 


Secf/on  B-B  from  below 
-ELEVATIONS    OF   TRESTLE    END    AND    DETAIL    OF    NEW    JOINT. 


and  around  the  trestle  so  as  to  make  it  a  fill.  Dumping  begins  at  the 
end  of  the  trestle  near  the  pit.  The  train  approaches  the  dump  with 
the  engine  behind;  when  the  first  car  is  at  the  end  of  the  filled  part  of 
the  trestle,  it  is  dumped,  pushed  ahead  on  the  trestle  and  the  next  car 
dumped.  In  this  way  the  light  trestle  has  to  support  empty  cars  only. 
There  is  always  an  inclined  face  or  toe  to  the  fill  which  exerts  a  consider- 
able pressure  on  the  posts  of  the  bents  which  it  surrounds,  as  shown  in  the 


314 


DETAILS  OF  PRACTICAL  MINING 


illustration.  The  tendency  is  to  push  the  posts  out  from  under  the  caps. 
To  prevent  this,  longitudinal  braces  are  usually  set  between  the  posts 
under  the  stringers.  At  the  Leonard  mine  in  a  recent  trestle,  these 
braces  were  omitted  and  the  posts  framed  into  the  caps  for  an  inch  or 
two  in  a  sort  of  box,  the  joint  A,  indicated  in  the  front  elevation  of  the 
bent,  being  made  as  shown  in  detail  in  the  lower  p^,rt  of  the  illustration. 
This  evidently  prevents  the  posts  frorn  being  pushed  through,  and  in 
practice  has  proved  satisfactory.  It  saves  the  entire  cost  of  the  braces 
and  also  the  labor  of  setting  them,  while  the  labor  of  framing  in  this 
manner  is  little  more  than  for  the  former  method. 

Wood  Trestle  for  Motor  Tramming. — From  the  typical  iron-range 
shaft  several  trestles  usually  lead  off,  one  or  two  for  the  ore  stockpile, 


r -/0-° *! 

~  ' 


Support  and  Brace 
every  6-.. 


FIG.    245. CONSTRUCTION     OF    A    TYPICAL     TRAMMING    TRESTLE. 

one  for  the  waste  rock  and  a  short  one  for  a  tail  track,  when  motor 
tramming  is  employed.  The  bents  of  these  trestles  are  sometimes  steel, 
more  frequently  wood,  and  in  the  latter  case  are  often  temporary.  The 
accompanying  illustration,  Fig.  245,  represents  a  rather  typical  bent  of 
light  construction.  It  is  designed  for  a  load  of  10  tons,  that  is,  a  loaded 
car  and  an  electric  locomotive.  The  material  specified  is  hemlock, 
except  for  the  posts  which  are  cedar,  spruce,  or  tamarack  round  poles. 
Such  a  trestle  will  range  in  height  from  15  to  50  ft.,  although  for  the  higher 
structures,  three  or  four  posts  are  used  in  the  bent.  The  stringers, 
instead  of  being  sawed  timber,  are  frequently  hewed  poles,  which  may 
be  lapped  and  the  corbels  eliminated.  The  full  sill  shown  here  is  often 
omitted  on  a  temporary  bent  and  1  X  6-ft.  bearing  blocks  used  under 
the  various  posts. 


TIMBER  STRUCTURES 


315 


Permanent  Stockpile  Trestle  of  Wood  (By  Oscar  Gustafson).— 
The  Colby  Iron  Mining  Co.,  operating  the  Colby  and  Ironton  mines  on 
the  Gogebic  range,  has  in  use  a  wooden  stockpile  trestle,  which  is  de- 
signed to  be  permanent  and  is  giving  great  satisfaction.  Besides  not 
having  to  be  taken  down  each  year,  it  differs  from  the  trestle  in  common 
use  chiefly  in  that  the  bents  have  but  one  leg  instead  of  two.  Loading 
tracks  are  laid  on  each  side  of  the  stockpile,  and  the  one  line  of  legs  spaced 
32  ft.  apart  offers  but  little  difficulty  to  steam-shovel  loading.  It  is  an 
advantage  to  both  the  railroad  and  mine  to  have  a  loading  track  on  each 
side  of  the  stockpile^  for  after  finishing  the  first  cut  the  end  of  the  loading 
track  is  thrown  over  and  the  shovel  runs  back  on  this  track  and  starts  a 


JZxl2x7'- 
Cap 


•12x12x4 
Corbel 


•-6xl2'8toX         \ 
^IkKail  flafe  ' 

jxS'x/4' 

RJxl2'Fir-> 
»~&:0-' -> 


PIG.    246. ELEVATIONS    OP    MAIN   BENT,    SIDE   BENT    AND    ANCHORAGE. 

cut  on  the  other  side  of  the  pile  without  waiting  for  the  first  track  to  be 
placed  again  and  connected.  This  saves  considerable  time  to  the  shovel 
and  crew.  While  the  shovel  is  working  on  the  second  cut,  the  railroad 
section  crew  has  plenty  of  time  to  place  the  first  track  and  is  not  com- 
pelled to  call  in  an  extra  gang.  The  trestle  is  found  to  be  cheaper  than 
the  old  trestle,  remains  in  alignment  better  while  loading  is  going  on, 
and  is  more  sightly. 

The  design  follows  broadly  that  of  the  Negaunee  permanent  steel 
trestle.  Each  bent  is  a  single  leg  of  12  X  12-in.  fir,  38  ft.  long,  on  which 
a  12  X  12-in.  fir  cap,  7  ft.  long,  is  mounted  and  braced  by  two  6X8- 
in.  by  6-ft.  fir  braces,  mortised  and  bolted  to  both  leg  and  cap.  To  each 
cap  are  bolted  two  12  X  12-in.  by  4-ft.  fir  corbels  or  bolsters,  to  which 
again  are  bolted  the  8  X  16-in.  by  32-ft.  fir  stringers,  as  shown  in  Fig.  246. 
The  stringers  are  trussed  with  16-lb.  rails;  to  each  end  of  these  a  %-in. 


316 


DETAILS  OF  PRACTICAL  MINING 


plate  is  riveted  and  then  bolted  to  the  stringer.  The  truss  rods  are 
blocked  in  the  center  with  a  6  X  12-in.  wood  piece.  To  the  stringers 
are  spiked  3-in.  planks  5  ft.  long,  and  the  30-lb.  rails  are  laid  on  the  planks 
at  30-in.  gage.  Outside  of  the  30-lb.  rail,  a  16-lb.  guard  rail  is  spiked. 

To  each  end  of  the  cap  is  bolted  a  plate  with  an  eye  in  the  end,  for 
attaching  the  guys.  These  guys  are  %-in.  galvanized-wire  strands;  they 
extend  out  to  side  bents  erected  at  100  ft.  from  the  trestle,  the  guys  from 
three  center  bents  being  attached  to  each  side  bent.  The  guys  pass 
over  the  cap  and  down  to  eye-bolts,  passing  through  a  12  X  12-in. 
by  16-ft.  timber  near  the  ground.  The  side  bents  are  32  ft.  high,  built 
of  round  timber  and  well  braced.  They  are  themselves  guyed  by  two 
%-in.  wire-rope  guys  to  a  "deadman,"  concreted  in  the  ground. 

Raising  Trestle  without  Ginpole  (By  R.  B.  Wallace). — The  apparatus 
shown  in  Fig.  247  was  devised  at  the  Republic  iron  mine  in  Michigan 


Clevis 


FIG.    247. MOVABLE    TRUSSED    POLE    FOR    RAISING    TRESTLE    BENTS. 

to  facilitate  the  erection  of  a  stockpile  trestle,  by  eliminating  the  opera- 
tions of  moving  a  ginpole,  changing  guys,  etc.,  which  consume  much 
time.  It  consists  of  a  sound  tamarack  pole  6  or  8  in.  in  diameter, 
supported  by  an  A-frame  at  the  center  and  trussed  by  a  J^-in.  wire  rope 
attached  to  both  ends  and  passing  over  the  top  of  the  frame.  The 
base  of  the  frame  and  the  crosspiece  at  the  lower  end  of  the  pole  are 
connected  by  two  J^-in.  rods.  A  roller  made  of  wood  with  both  ends 
incased  in  pipe  is  attached  to  the  base  of  the  frame  and  in  front  of  it, 
so  that  by  raising  up  the  lower  end  of  the  pole,  the  whole  apparatus  can 
be  easily  rolled  out  to  the  end  of  a  trestle.  With  the  lower  end  of  the 
pole  lashed  to  the  rails  or  to  a  stringer,  it  is  ready  for  use  in  hauling  up  a 
bent.  After  the  bent  is  hauled  up,  it  is  held  by  guy  lines  while  the 
stringers  are  raised  and  fastened  in  place.  Then  the  frame  is  rolled  out 
to  the  new  end  of  the  trestle,  and  is  made  fast,  ready  for  the  next  bent. 
An  electric  winch  is  used  for  power. 

Erecting  Trestle  Bents  with  Cableway  (By  A.  Livingstone  Oke). — 
The  diagram,  Fig.  248,  shows  a  convenient  method  adopted  for  erecting 
quickly  a  long  series  of  trestles  to  carry  an  inclined  gravity  tramway 
down  a  steep  hillside.  The  carpenters  built  the  trestles  on  .the  site, 


TIMBER  STRUCTURES 


317 


starting  with  the  last  on  the  lower  end  of  the  section  and  stacking  them 
in  ascending  order.  Meantime,  a  wire-rope  cableway  was  erected  by 
means  of  two  shears,  so  that  the  lowest  point  of  the  rope  was  above  the 
finished  tramway  level.  A  winch  was  set  at  the  upper  end,  as  shown. 
The  winch-line  operated  over  a  carrier  sheave  running  on  the  fixed  rope; 
it  had  a  weighted  hook  at  its  end  and  a  stop  placed  a  few  feet  above  it. 
The  hook  was  used  to  take  hold  of  the  bent  tops  and  the  rope  pulled  by 
the  winch  raised  the  bent.  The  stop,  catching  on  the  sheave,  brought 


Shears  \ 


FIG.  248.  -  PROFILE  OF  TRESTLE  AND  CABLEWAY. 

the  bent  clear  back  to  the  required  position,  once  it  was  swinging  clear 
of  the  ground.  Each  bent  was  temporarily  fastened  in  a  vertical  posi- 
tion by  extending  running  planks  from  the  top  of  the  bent  last  erected, 
until  the  permanent  bracing  was  put  in. 


GINPOLES 

A  Built-up  Ginpole  (By  A.  Livingstone  Oke).  —  It  frequently  happens, 
where  timber  is  scarce,  that  a  ginpole  or  other  long  timber  is  required 


Ends  butted 
/  together 


EH: 


METHOD  OF  ASSEMBLING* 


Lashings 

This  end  is  pinched 
under  the  Turns 


LASHIN&    METHOD 


End  pass  ed  around 
two  or  three  times 

FIG.    249. THREE    ROUND    TIMBERS   LASHED    TOGETHER    FOR    A    GINPOLE. 

larger  than  any  single  stick  on  hand.  A  method  of  building  one  from 
short  lengths  of  either  round  or  square  timber  is  exhibited  in  Fig.  249. 
The  poles  are  laid  up  in  threes,  the  ends  overlapping,  as  shown,  with  a 
lashing  on  both  sides  of  each  joint;  the  number  of  turns  of  rope  used 
depends  on  whether  the  pole  has  to  sustain  merely  a  thrust,  as  in  a 
ginpole,  or  is  to  be  employed  for  work  in  which  it  will  be  subjected  to 


318  DETAILS  OF  PRACTICAL  MINING 

bending  stresses.  In  the  latter  case,  both  the  strength  of  the  ropes,  the 
number  of  turns  and  the  tightness  with  which  they  are  put  on,  must  all 
be  increased.  If  the  poles  available  are  all  of  the  same  length,  but  of 
different  diameters,  some  care  must  be  used  in  matching  the  sizes  at 
different  points  in  the  length  of  the  built-up  pole,  keeping  the  stouter 
ones  together  and  gradually  tapering  to  the  smaller  end.  Poles  may 
also  be  built  with  more  than  three  members,  but  this  number  is  the 
more  satisfactory,  when  possible,  as  it  makes  a  three-point  support  in- 
side and  prevents  transverse  movement.  The  proper  method  of  lashing 
is  also  shown;  several  turns  of  small  rope  are  to  be  preferred  to  fewer 
turns  of  a  larger  rope.  One  end  of  the  rope  is  pinched  under  the  turns 
and  finally  the  free  end  taken  around  these  by  passing  through  several 
times,  as  shown,  and  the  whole  drawn  up  tight.  To  tighten  the  lash- 
ing further,  short  lengths  of  smaller  rope  may  be  passed  around  the 
turns  on  the  other  two  sides  as  well  and  drawn  as  taut  as  possible. 

Ginpole  of  10-in.  Pipe. — A  ginpole  used  by  the  Oliver  company  in 
the  Chisholm  district  on  the  Mesabi  range  in  constructing  its  stockpile 
trestles  is  herewith  illustrated.  It  is  built  of  10-in.  pipe  reinforced  against 
possible  buckling  by  pieces  of  round  fir  about  3  ft.  long  inserted  three  to 
a  length  of  pipe  and  bolted  to  keep  them  from  slipping.  The  stockpile 
trestles  run  from  40  to  50  ft.  in  height  usually  and  the  ginpole  will  reach 
perhaps  20  ft.  above  the  floor  of  the  trestle.  Details  of  the  pole  are 
shown  in  Fig.  250.  About  5  ft.  from  the  top  a  horizontal  arm  is  rigidly 
attached;  it  is  made  of  a  stout  T-rail  and  is  held  to  the  pole  by  an  iron 
strap  and  also  by  an  inclined  stay-rod  of  round  iron,  yoked  at  the  top 
to  embrace  the  top  of  the  pole,  to  which  it  is  bolted,  and  looped  under  the 
head  of  the  rail  at  its  lower  end.  The  web  of  the  rail  is  cut  away  to  per- 
mit this  looping  and  the  head  and  base  held  together  by  a  bolt.  Near 
each  end  of  the  rail  a  clip  is  bolted,  the  upper  part  being  a  clevis  to  em- 
brace the  web  and  base  of  the  rail  and  the  lower  part  pierced  to  allow 
blocks  to  be  hung.  One  double  and  one  single  block  are  used  for  hoisting. 

About  20  ft.  down  from  the  top  the  pole  is  held  against  the  trestle 
by  a  horizontal  timber,  6  X  10  in.  in  section  and  about  10  ft.  long,  tapered 
somewhat  at  the  end  next  the  pole  and  framed  to  fit  the  pole;  the  bear- 
ing is  completed  at  this  point  by  a  J/£  X  6-in.  strap  bolted  to  the  timber 
and  passing  around  the  pole,  thus  permitting  rotation.  The  timber  is 
fastened  to  the  decking  of  the  trestle.  The  lower  end  of  the  ginpole 
is  closed  with  a  plate  having  a  hole  in  the  center  to  fit  a  foot-piece  bear- 
ing. This  bearing  piece  is  a  casting  with  a  square  base  containing 
four  bolt  holes  and  a  vertical  cylindrical  portion.  About  4  ft.  above  the 
bearing  two  opposite  holes  in  the  pipe  permit  the  insertion  of  a  bar 
with  which  the  pole  is  turned  on  the  bearing  described.  A  rough  sup- 
porting platform  is  built  of  heavy  planks  and  hewn  timber. 


TIMBER  STRUCTURES 


319 


This  ginpole  is  not  used  for  erecting  the  trestle  bents,  which  are 
framed  on  the  ground  and  hoisted  with  a  wooden  pole,  but  a  great  deal 
of  material  goes  into  the  trestle,  such  as  flooring,  rails,  railings,  trolley- 
wire  supports,  etc.,  and  there  is  no  way  of  getting  this  up  from  the  ground 


-Clips  bolted— 

Double  Sheave  J3        j0  Ra// 

Block-— *\o\        Single  Shear* ° 
Block  


Supporting  Platform  w 
PIG.    250. DETAILS   OF    GINPOLE    RIGGED    FOR    HOISTING. 

except  by  the  use  of  some  special  device,  since  the  shafts  are  not  equipped 
with  cages  and  the  skips  are  inconvenient  as  well  as  being  usually  other- 
wise engaged. 

Handling  Stack  with  a  Ginpole   (By  A.  Livingstone  Oke). — The 
proper  method  of  placing  stacks  or  columns  on  their  foundations,  using 


320 


DETAILS  OF  PRACTICAL  MINING 


a  single  ginpole  is  shown  in  Fig.  251.  While  not  new,  it  is  probably  not 
known  to  all.  There  should  be  two  guy  ropes  at  thfe  back,  secured 
firmly,  so  that  the  pole  has  a  good  cant  toward  the  pull  of  the  tackle. 
The  lashing  must  be  placed  on  the  stack  as  far  above  the  center  of  gravity 
as  the  available  height  of  the  ginpole  allows,  the  distance  a  always 
being  kept  greater  than  6,  after  making  due  allowance  for  the  length 
taken  up  by  the  tackle  itself.  The  power  may  be  applied  from  a  wind- 
lass or  by  direct  pull,  depending  on  the  weight  to  be  handled.  The  more 
nearly  vertical  the  pull  the  better,  a  snatch-block  being  necessary  if 
the  windlass  is  not  directly  below  the  lifting  tackle. 


Clove  Hitches 
Chain  or  rope  strap 


Stick  Foundation      Center  of  gravity  of  stack 

FIG.    251. — RIGGING   OF   GINPOLE    AND   TACKLE    FOB   SETTING   STEEL   STACK. 


VARIOUS  DEVICES 

Substructure  of  Wooden  Water  Tank. — A  necessary  adjunct  to 
every  Iron-Range  boiler  planti  s  the  water  tank.  The  flat  topography 
usually  eliminates  the  possibility  of  setting  the  tank  on  high  ground 
to  gain  head,  and  for  that  reason  it  is  usually  put  near  the  boiler  house. 
The  latest  tanks  are  of  the  elliptical-bottom  steel  type,  raised  to  con- 
siderable heights  on  steel  structures,  but  wooden  tanks  supported  on 
wooden  substructures  in  the  manner  of  railway  tanks  are  still  common. 
Such  a  substructure  of  standard  type  is  illustrated  in  Fig.  252.  It  is 
built  of  sawed  timber  set  on  concrete  piers  and  usually  painted.  The 
tank  supported  in  this  case  is  12  X  12  ft. 

Surface  Steam-line  Supports. — In  the  Norrie  group  of  mines  at  Iron- 
wood,  Mich.,  steam  is  conveyed  some  distance,  from  the  boiler  house  to 


TIMBER  STRUCTURES 


321 


the  hoist  at  one  of  the  shafts.  The  outdoor  steam  pipe  is  carried  on  struc- 
tural-steel bents  in  order  to  maintain  the  desired  grade  over  the  variable 
ground.  The  bents  are  spaced  about  15ft.;  at  every  200  ft.  approxi- 


FIG.    252. POSTS,    STRINGERS    AND   BRACING    TO    CARRY   WOODEN   TANK. 


i  ."*"**.  i       ^  5'An9le 


12  "Plank 


Sheathing 


FIG.    253. TOP    OF    A   BENT    CARRYING    A    STEAM    PIPE. 

mately  a  slip  joint  is  inserted  to  take  care  of  expansion.  This  is  carried 
on  a  more  elaborate  structure.  The  bents  are  set  on  concrete  foundations 
to  which  they  are  held  by  plates  bent  at  an  angle,  riveted  to  the  legs 

01 


21 


322 


DETAILS  OF  PRACTICAL  MINING 


and  bolted  to  the  concrete.  A  3  X  12-in.  plank,  supported  on  angles 
along  one  side,  serves  as  a  walk  when  it  is  necessary  to  inspect  the  pipe 
or  pack  the  slip  joints.  The  cross-braces  are  spaced  3^  ft.  center  to 
center  and  as  many  are  used  as  the  height  of  the  bent  requires.  The 
manner  of  holding  the  pipe  on  the  top  of  the  bent  so  as  to  permit  longi- 
tudinal motion,  as  shown  in  Fig.  253,  is  of  interest.  The  pipe  is  jacketed 
with  insulating  material  and  sheathed  in  galvanized  iron,  wired  on.  A 
cast  saddle  at  each  bent  is  bolted  to  the  bottom  of  the  pipe  with  two 
%-in.  bolts  over  the  top.  The  bottom  of  this  casting  is  a  socket  which 
fits  over  a  short  section  of  2-in.  pipe.  This  pipe  acts  as  a  roller;  it  is 
free  to  roll  longitudinally  on  a  plate  which  forms  the  top  of  the  bent, 


I*  Bolt 
l"Hole  for%  S,  Hooks*   Driven  in  j 


.  | 

2- 10'x  10" Timbers       KJ6*-; 
.bo/fed  together 

FIG.    254. DETAILS    AND    ASSEMBLY   OP   DERRICK. 

but  is  held  against  lateral  motion  by  1  X  1-in.  pieces  riveted  to  the  plate. 
The  details  of  construction  of  the  top  of  the  bent  are  evident  from  the 
drawing. 

Simple  Guyed  Derrick  (By  H.  L.  Botsford). — The  derrick  shown  in 
Fig.  254  is  one  readily  constructed  by  a  mine  carpenter  and  blacksmith. 
It  is  useful  for  handling  buckets  at  the  beginning  of  shaft  sinking  opera- 
tions, as  well  as  for  many  other  purposes  about  a  mine. 

Dipping  Tank  for  Mine  Timber  (By  L.  0.  Kellogg).— At  the  Bennett 
mine,  on  the  Mesabi,  Carbolineum  is  rather  extensively  used  for  treating 
timber  for  both  underground  and  surface  construction.  The  material 
for  such  surface  structures  as  the  coal  trestle  and  the  casing  on  the  ver- 
tical water-tank  pipe  and  for  the  shaft  sets  and  station  timbering  under- 
ground is  dipped  in  the  preservative  before  it  is  put  in  place.  The 


TIMBER  STRUCTURES 


323 


tank  used  for  the  purpose,  shown  in  Fig.  255,  is  simple  enough,  but  has 
proved  convenient  and  is  so  readily  constructed  as  to  merit  description. 
It  is  built  of  2-in.  lumber  throughout,  except  that  the  two  end  sills 
are  4  X  4  in.  Its  length  is  such  as  to  accommodate  the  wall  plates  of 
the  shaft  sets,  the  longest  pieces  which  require  treatment.  The  boards 
in  the  box  itself  are  tongue-and-grooved  and  are  bolted  together  to  get 
tight  joints.  A  longitudinal,  vertical  partition  divides  the  tank  into  two 
compartments,  one  for  dipping,  and  other  for  draining,  the  former 


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PIG.    255. WOODEN   TANK    FOR   TREATING    TIMBER    WITH    PRESERVATIVE. 

somewhat  the  larger.  The  box  is  bound  with  sets  of  2  X  4-in.  material, 
consisting  of  a  sill  and  two  posts  each,  spaced  about  2  ft.  apart.  The 
dipping  compartment  is  lined  bottom  and  sides  to  a  height  of  about  18 
in.  with  galvanized  iron  nailed  to  the  wood  and  soldered  at  the  joints. 
A  steam  coil  on  the  bottom  along  the  sides  and  one  end  keeps  the  Car- 
bolineum  slightly  warm,  to  obtain  a  more  rapid  penetration.  The 
timber  is  allowed  to  soak  for  a  few  minutes  and  then  lifted  out  to  drain 
on  several  2  X  4-in.  crosspieces  above  the  drain  compartment. 


VIII 
HOISTING,  LOWERING,  TRANSPORTING 

Hoisting  Devices — Lowering  Devices — Signaling — Windlass  and  Whim 
— Rollers  and  Sheaves — Rope — Transporting — Accessories 

HOISTING  DEVICES 

Cableway-and-carrier  Bucket  Hoist  (By  R.  B.  Wallace). — An  un- 
usual hoisting  arrangement  is  in  use  for  some  small-scale  work  at  the 
property  of  the  Republic  Iron  Co.,  Republic,  Mich.  A  cable  is  stretched 
across  an  old  openpit  from  the  tower  to  a  point  over  the  shaft  opening 
which  lies  on  the  other  side  and  at  the  bottom  of  the  pit.  A  cableway 


FIG.    256. LAYOUT    OF    CABLEWAY,    HEADFRAME,    HOIST    AND    SHAFT. 

carriage  runs  across  the  pit  on  this  cable  and  carries  the  bucket;  at  the 
lower  end  it  automatically  releases  the  bucket  and  drops  it  into  the  shaft. 
The  general  relations  are  shown  in  Fig.  256.  This  shaft  descends  at 
about  85°,  and  enters  some  old  workings  where  floors  and  pillars  are 
being  cleaned  up.  The  hoisting  is  done  by  electricity  and  the  bucket 
is  landed  by  the  engineer.  At  the  completion  of  a  hoist,  the  carriage  is 
automatically  held  stationary  while  the  bucket  is  allowed  to  descend 
to  the  lander's  platform.  When  the  bucket  has  been  hoisted  up  to  the 
carriage  again,  the  moving  of  a  lever  in  the  engine  house  releases  the 
carriage.  Two  buckets  are  used,  one  being  filled  while  the  other  is 

324 


HOISTING,  LOWERING,  TRANSPORTING  325 

hoisted.  The  diameter  of  the  track  rope  is  1  J£  in.,  and  of  the  hoist  rope, 
%  in.  The  capacity  of  the  bucket  is  0.6  ton.  In  an  awkward  situation, 
such  as  this,  where  the  quantity  of  ore  does  not  warrant  an  elaborate 
hoisting  plant,  this  scheme  works  satisfactorily. 

Otis  Elevator  Mine  Hoist  (By  L.  E.  Ives). — The  Naumkeag  Copper 
Co.  about  a  mile  west  of  Houghton,  Mich.,  started  exploratory  work 
with  an  adit,  the  mouth  of  which  is  about  on  a  level  with  the  wagon  road 
and  about  75  ft.  from  it.  Because  of  the  lack  of  elevation  and  the  prox- 
imity of  the  road,  dump  room  at  the  mouth  of  the  adit  was  difficult  to 
obtain.  The  difficulty  was  overcome  in  a  rather  novel  and  effectual 
manner. 

An  artificial  single-compartment  shaft  was  constructed  by  the  Otis 
Elevator  Co.,  over  the  adit  at  its  mouth.  The  framework  of  the  shaft 
was  built  up  of  flat,  rough  boards,  approximately  7}^  in.  wide  and  1% 
in.  thick.  Five  of  these,  laid  flat  sides  together  and  standing  on  end  con- 
stituted each  corner  post,  these  being  about  8^  in.  thick.  The  sides 
were  divided  in  panels  by  horizontal  members  of  similar  construction, 
each  panel  braced  diagonally.  This  framework  was  inclosed  by  matched, 
planed  boards  8  X  %  in.,  the  whole  making  up  the  boxed-in  shaft, 
9  X  10  ft.  7  in.  outside  dimensions.  The  lift  from  the  floor  of  the  tunnel 
to  the  level  of  the  dump  was  30  ft. 

The  elevator  car  was  nothing  more  than  an  ordinary  freight-elevator 
platform  with  a  2-ft.  gage  track  running  across  it  and  two  sides  boarded 
to  a  height  of  5  ft.,  the  car  itself  being  8  ft.  long.  The  hoisting  was  done 
by  a  10-hp.,  alternating-current,  230-volt,  2-phase,  60-cycle  motor, 
placed  in  a  separate  compartment  over  the  sheaves  at  the  top  of  the  shaft. 
Two  %-in.  steel  hoisting  cables  were  used  and  the  hoisting  speed  was  40 
ft.  per  minute.  The  tram  car  held  30  cu.  ft.,  and  the  hoist  was  capable 
of  lifting  4000  lb.,  in  addition  to  the  elevator  car.  The  entire  installation 
was  operated  by  a  hand  cable,  the  stopping  being  automatic  at  both  top 
and  bottom.  . 

Power  for  operating  was  obtained  from  the  service  wires  of  the 
Houghton  County  Electric  Light  Co.,  not  over  100  ft.  away.  When 
hoisting  about  600  tons  of  rock  per  month  the  power  consumption  was 
about  58  kw.-hr.  per  month,  at  a  total  cost  of  $1.80.  This  figures  out 
about  0.3  cts.  per  ton  hoisted.  No  hoistmen  were  required.  Two  tram- 
mers pushed  the  car  out  to  the  shaft  and  to  the  platform,  pulled  the 
cable,  went  up  with  the  load,  dumped  it  and  returned  to  the  muck  pile 
again.  Power  was  not  wasted  when  no  hoisting  was  going  on,  and  three 
safety  stops  guarded  against  the  possibility  of  overwinding. 

Chain-driven  Convertible  Hoist  (By  E.  E.  Carter). — A  steam-driven, 
double-drum,  geared  hoist  at  the  Gold  Hill  mine,  Quartzburg,  Idaho,  was 
changed  into  an  electric  hoist  by  disconnecting  the  driving  and  valve 


326 


DETAILS  OF  PRACTICAL  MINING 


rods  and  substituting  a  gear  on  the  crank  disk.  With  this  combination 
the  hoisting  speed  was  450  ft.  per  minute.  The  motor  ran  at  850  r.p.m., 
and  both  motor  and  hoist  were  operated  considerably  below  rated  capacity. 
Steel  and  rawhide  pinions  were  tried  and  found  unsatisfactory.  Both 
gear  and  pinion  gave  constant  trouble  from  excessive  wear,  the  teeth  in 
the  case  of  the  steel  gears  becoming  crystallized  and  falling  out.  Further- 
more, the  vibration  was  carried  to  the  motor  and  thus  resulted  in  the 
motor  connections  shaking  loose,  making  it  necessary  to  keep  an  extra 
one  on  hand  for  frequent  changes. 


Controller 


87-Teeth-C.l. 


Steel  23-Teefh,  6'Diam. 

52-Hp.  Variable.  Speea 
Reversible 

J>  Induction  Motor  850  R.p.m. 
440-Yolts 

FIG.    257. STEAM    HOIST    ARRANGED    FOR    ELECTRIC    DRIVE. 

• 

This  arrangement  was  a  constant  source  of  expense,  as  well  as  a  loss 
of  time;  therefore,  the  following  arrangement  was  tried  with  success: 
An  SJ^rin.  silent-chain  drive  was  substituted  for  the  gears,  set  at  36-in. 
centers,  and  arranged  as  shown  in  Fig.  257.  After  this  drive  had  been 
in  operation  for  sufficient  time  to  prove  its  efficiency,  no  sign  of  wear 
was  apparent  and  no  time  had  been  lost  because  of  mishap  to  the  hoist 
after  its  installation.  The  hoist  picked  up  its  load  much  easier  than  it 
did  with  the  gears  or  even  better  than  it  did  with  steam.  There  was  no 
trouble  with  the  "flop"  of  the  chain,  when  reversing,  as  was  anticipated. 

The  cost  of  the  chain  installation  was  practically  the  same  as  for  the 
original  gear  drive.  Experience  elsewhere  has  shown  that  the  wear  on 


HOISTING,  LOWERING,  TRANSPORTING  327 

these  chains  is  confined  almost  entirely  to  the  pins.  As  the  chain 
lengthens  because  of  wear  and  the  pitch  becomes  greater,  the  chain  will 
ride  higher  on  the  gears  and  thus  give  warning  a  long  time  before  it  is 
necessary  to  put  in  new  pins.  The  cost  of  new  pins  is  nominal  and  they 
may  be  put  in  easily.  This  chain  was  expected  to  last  between  three 
and  four  years  before  repairing  with  new  pins. 

The  52-hp.,  variable-speed,  440- volt,  alternating-current  motor  was 
set  on  a  concrete  foundation  with  a  subbase  and  suitable  slide  to  allow 
adjustment  of  the  chain.  The  chain  ran  comparatively  loose.  A 
hoisting  speed  of  more  than  600  ft.  per  minute  was  the  rule  instead  of 
450  ft.  as  formerly.  The  chain  was  removed  at  intervals  and  cleaned 
thoroughly  with  gasoline,  then  allowed  to  dry,  and  lubricated  with  Albany, 
Keystone  or  a  suitable  cup  grease,  previously  warmed  so  as  to  work  in 
around  the  pins ;  any  excess  was  wiped  off.  It  was  lubricated  at  intervals 
as  required  with  the  same  lubricant.  Mica  axle-grease  or  graphite 
should  not  be  used.  The  possibility  of  disconnecting  the  gear  from  the 
crank  disk  and  replacing  the  driving  rods,  etc.,  allows  a  change  from 
electric  to  steam  or  air  power  within  a  short  time,  which  is  desirable  when 
power  troubles  are  frequent. 

Balancing  Dummy  in  Inclined  Shaft  (By  L.  Hall  Goodwin). — In 
the  inclined  shafts  of  the  Lake  Superior  district  it  is  the  custom  to  hoist 
in  balance;  the  practice,  however,  is  different  from  that  used  generally 
throughout  the  West  in  that  the  drums  are  not  designed  to  clutch  in 
and  out  of  balance  but  both  ropes  are  wound  on  the  same  drum  so  that 
the  position  of  one  skip  in  the  shaft  relative  to  the  other  is  always  fixed. 
Mines  in  the  development  stage  usually  sink  and  timber  the  two-hoist- 
ing-compartment shaft  in  final  form,  except  that  rail  stringers  are  put 
in  one  road  only  and  hoisting  is  carried  on  unbalanced  until  the  shaft 
has  attained  a  considerable  production,  when  rails  are  put  in  the  other 
road  and  the  second  skip  put  in  service.  At  the  Houghton  Copper 
mine,  a  small  development  property  on  the  Superior  lode  just  north  of 
the  Superior  mine,  a  novel  method  of  securing  balanced  hoisting  from 
the  start  was  employed. 

Track  stringers  were  laid  in  the  south  road  only,  but  in  the  north 
road  rails  of  usual  weight  were  laid  on  the  12  X  12-in.  sleepers  to  carry 
a  dummy.  These  rails  were  laid  in  the  center  of  the  roadway  with  a  2- 
ft.  gage,  so  that  when  permanent  stringers  were  put  in  they  would  be 
laid  outside  of  the  present  rails,  and  the  latter  would  be  simply  trans- 
ferred to  them  as  the  work  progressed.  The  dummy  was  made  of  riveted 
sheet  iron  and  filled  with  iron  scrap,  being  2  X  2  ft.  in  section  and  6  ft.  long. 
A  point  in  its  construction  was  a  pivoted  rear  axle,  which  swung  freely 
on  a  pinion  projecting  from  the  lower  end  of  the  dummy.  This  allowed 
the  four  wheels  to  accommodate  themselves  to  irregularities  in  the 


328 


DETAILS  OF  PRACTICAL  MINING 


narrow  track,  which  in  this  improvised  arrangement  were  probably 
pronounced,  and  minimized  the  possibility  of  the  dummy's  jumping  the 
rails. 

The  main  reason  for  the  adoption  of  this  device  was  the  need  of  cut- 
ting down  the  heavy  power  demand  when  starting  an  unbalanced  skip. 
The  contract  with  the  power  company  imposed  a  penalty  for  peak  load 
at  all  times  and  an  additional  penalty  for  load  on  the  company's  light- 
ing peak.  The  penalty  would  be  nearly  four  times  as  great  with  an  un- 
balanced skip  as  with  the  arrangement  described,  and  a  larger  hoist 
motor  would  also  be  required. 

Fleeting  Device  for  Hoist  with  Conical  Drums  (By  F.  H.  Arm- 
strong).— On  the  Brier  Hill  hoist  of  the  Penn  Iron  Mining  Co.,  Vulcan, 


FIG.    258. DIAGRAM    OF    FLEETING    DEVICE. 

Mich.,  are  two  12-ft.  cylindrical  drums,  one  for  the  skip  and  the  other 
for  the  cage.  There  are  also  two  conical  drums,  from  4^  to  17  ft.  in 
diameter,  which  are  used  for  counterbalancing  the  dead  loads.  The 
hoist  is  located  so  near  to  the  headframe  that  the  sheave  to  which  the 
counterbalance  rope  leads  is  in  line  with  one  end  of  the  conical  drum, 
thus  pulling  heavily  sidewise  on  the  deep  grooves.  To  correct  this  a 
channel-iron  track  was  set  up  in  the  hoist  house,  in  which  runs  a  carriage 
carrying  a  sheave.  The  carriage  and  sheave  are  pulled  up  the  track  by 
a  rope  leading  from  the  carriage  to  a  drum  that  is  driven  by  a  worm  and 
wormwheel  from  the  main  shaft  of  the  conical  drum.  The  speed  of 
this  small  drum  is  such  that  it  pulls  the  carriage  across  the  face  of  the 


HOISTING,  LOWERING,  TRANSPORTING  329 

conical  drum  the  distance  between  two  adjacent  grooves  for  every  com- 
plete revolution  of  the  conical  drum.  Fig.  258  shows  the  carriage,  sheave, 
track  and  rope  leading  to  the  small  drum. 

Automatic  Skip  Recorder. — The  Franklin  Mining  Co.,  in  the  Lake 
Superior  copper  district,  is  using  on  its  hoist  at  the  Franklin  Jr.  mine  an 
automatic  recording  device  which  provides  a  permanent  record,  on 
paper,  of  every  movement  of  the  skip  during  a  12-hr,  period.  The 
mechanism  is  comparatively  simple.  Two  drums  are  mounted  on  vertical 
spindles,  about  12  in.  apart,  and  these  drums  contain  a  paper  chart. 
The  paper  travels  from  right  to  left,  the  left-hand  drum  being  driven  by 
clockwork.  The  chart  is  divided  longitudinally  according  to  hours 
and  minutes,  from  6  a.m.  to  7  p.m.,  or  vice  versa.  A  vertical  arm,  bear- 
ing an  ink  pen,  containing  red  ink,  registers  both  rTorizontal  and  vertical 
lines  on  this  chart,  and  receives  its  motion  through  a  chain  sprocket  and 
gears  from  the  countershaft  of  the  hoist.  There  is  also  a  lower  arm  on 
the  machine  which  can  be  connected  to  the  electric-signal  system  so 
as  to  operate  a  pencil  vertically  across  the  lower  line  of  figures  on  the 
chart,  and  thus  show  the  time  at  which  any  signals  are  rung. 

Before  the  device  was  installed,  there  was  no  way  of  checking  con- 
flicting statements  of  the  hoisting  engineer  and  the  men  underground, 
in  disputes  arising  as  to  the  position  of  the  skip  at  any  time.  In  cases 
where  hoisting  was  held  up,  the  underground  dumpers  would  be  likely 
to  say  that  they  could  not  get  the  skip,  which  was  lying  idle  at  some 
level  above  or  below  them.  The  engineer,  on  the  other  hand,  would 
claim  that  the  signals  were  not  rung  and  that  there  was  nothing  wrong 
with  the  skip.  With  this  recorder  in  operation,  it  is  impossible  for 
any  such  dispute  to  arise.  The  chart,  as  illustrated  in  Fig.  259,  shows 
exactly  where  the  skip  was  at  any  hour  or  minute  of  the  day  and  how 
long  it  took  to  make  any  trip;  the  speed  of  hoisting  or  lowering  can  be 
computed  from  the  figures,  since  the  vertical  divisions  on  the  chart 
show  the  positions  of  the  various  levels  in  the  mine.  The  only  atten- 
tion the  recorder  needs  is  the  filling  of  the  pen  with  ink  every  day  and 
the  occasional  oiling  of  the  parts.  The  engineers  like  the  device  be- 
cause it  places  the  responsibility  where  it  belongs.  The  charts  are  re- 
moved daily  and  filed  in  the  office  of  the  superintendent,  where  they 
are  kept  for  several  months.  The  recorder  is  the  invention  of  J.  M.  & 
O.  R.  Johnson,  Ishpeming,  Mich. 

LOWERING  DEVICES 

Go-devil  Incline  Plane. — At  the  North  Star  mine,  Grass  Valley, 
Calif.,  the  narrow  quartz  vein,  dipping  only  23°,  is  developed  by  main 
levels  at  300-ft.  intervals  on  the  dip.  The  ore  is  conveyed  to  small 


330 


DETAILS  OF  PRACTICAL  MINING 


John.on  R»cor<l«r  for  Minn.  P.t  Oct.  5th.  1J09.  Mfd.  by  J.  M.  A  0.  R.  John.on,  l.hp.mlng, 


The  Franklin  Mining  Company 
No.  1  Amygdaloid  Shaft 


PIG.  259. SAMPLE  OP  GRAPHIC  RECORD,  BREAKS  REPRESENTING  CURVES  OF  UNIN- 
TERRUPTED HOISTING. 


HOISTING,  LOWERING,  TRANSPORTING 


331 


bins  along  these  levels  by  means  of  gravity  planes  through  the  stopes. 
As  the  stope  is  carried  up,  the  incline  track  is  extended,  the  headsheave 
block  being  kept  at  the  top  of  the  stope,  hung  from  a  heavy  stull.  Tracks 
branch  off  horizontally  in  both  directions  from  the  head  of  the  incline, 
a  turnsheet  being  set  between  the  top  of  the  incline  and  the  head-block 
post.  The  cars  that  are  filled  along  the  horizontal  tracks  are  brought 
to  the  turnsheet,  attached  to  the  rope  and  lowered  in  balance  against  the 
1  car  last  sent  down  and  still  attached,  empty,  to  the  other  end  of  the  rope 
at  the  bottom  of  the  incline.  The  whole  system  is  called  a  "go-devil." 
The  head-block  is  probably  the  most  interesting  feature.  It  is  il- 
lustrated in  Fig.  260.  The  rope  passes  up  on  the  outside  of  the  outside 


Lf-3"..>l          Li: 
Details  of  Brake  Block 

FIG.    260. TRIPLE-SHEAVE    HEAD  BLOCK    FOR    GRAVITY    PLANE. 

blocks,  down  the  inside  through  grooves  in  the  brake  block,  and  around 
the  bottom  of  the  lower  sheave.  The  brake  block  is  triangular,  pivots 
about  its  center  in  between  the  three  sheaves  and  is  operated  by  a  handle 
attached  to  the  square  head  shown.  It  is  brought  to  bear  on  all  three 
sheaves  and  thus  gives  a  strong  braking  effect.  It  can  be  locked  in  posi- 
tion by  extending  the  handle  with  a  piece  of  pipe  and  connecting  the  end 
of  this  to  a  lever  with  a  ratchet  lock  set  on  a  stout  post.  The  two 
halves  of  the  triangular  spider-frame,  the  three  sheaves  and  the  brake 
block  make  six  castings  entering  into  the  device,  beside  the  bolt,  nuts 
and  handle.  The  block  is  suspended  by  a  bolt  through  the  post  and  by 
a  chain  so  as  to  lie  in  approximately  the  same  plane  as  the  ropes  of  the 
descending  and  ascending  cars. 


332 


DETAILS  OF  PRACTICAL  MINING 


A  %-in.  steel- wire  rope  is  used  and  is  attached  by  means  of  the 
safety  hook  shown  in  Fig.  261.  The  cars  are  in  general  of  two  types. 
That  formerly  used  was  built  of  wood  bound  with  strap  iron,  and  had  a 
vertical  front.  The  door  was  hinged  at  the  top  and  was  held  by  a  bottom 
latch,  which  was  tripped  by  a  block  beside  the  track  just  as  the  dumping 
point  was  reached.  These  cars  were  of  different  sizes,  but  were  rather 
small,  holding  about  1000  Ib.  They  have  been  almost  entirely  displaced 
by  the  car  shown  in  Fig.  261.  This  car  is  built  rigid  throughout  and  its 
emptying  is  facilitated  by  the  inclined  end.  Its  strength  is  one  of  its 
features,  as  it  has  to  withstand  extremely  hard  usage.  Its  capacity  is 
about  16  cu.  ft.  At  the  upper  end  are  a  number  of  hooks  of  strap  iron 
arranged  to  permit  coiling  excess  rope. 

Whichever  type  of  car  is  used,  it  is  dumped  by  partly  upsetting  at 
the  foot  of  the  incline,  which  is  the  top  of  the  bin;  the  bin  is  usually 


SIDE     ELEVATION 


END     ELEVATION 


A-E.YE  FOR  ROPE  HOOK 
FIG.    261.  -  GO-DEVIL   RIGID    CAB    AND    SAFETY    HOOK    FOR    ROPE    ATTACHMENT. 

built  of  wood  in  a  recess  blasted  out  of  the  foot-wall.  This  is  effected  by 
the  device  shown  in  side  elevation  in  Fig.  262.  The  last  2  ft.  of  the  incline 
tracks  are  made  steeper  and  a  round  timber  resting  against  two  inclined 
posts,  as  shown,  is  set  across  the  bottom,  over  the  last  tie.  The  wheels  of 
the  dumping  car  rest  on  this  bumper.  In  the  center  of  each  of  the  tracks 
is  a  hook,  usually  of  1%-in.  grooved  steel;  one  end  is  hooked  over  the 
next  to  the  last  track  tie,  the  other  projects  upward  so  as  to  catch  the 
front  axle  of  the  descending  car.  The  axle  is  caught  as  the  front  wheels 
hit  the  bumper.  The  inertia  of  the  car  and  of  its  contents  causes  it  to 
revolve  about  this  axle  and  to  tilt  up  until  the  top  of  the  body  rests  against 
the  crossrail  on  the  incline^  posts.  In  this  position  the  end  and  bottom 
of  the  car  are  at  an  angle  to  permit  easy  discharge  of  the  contents, 
aided  by  the  inertia  of  the  descent. 

The  cycle  of  operations  is  as  follows:  The  mucker  or  trammer  fills 
a  car  at  some  point  along  the  lateral  tracks;  he  trams  it  to  the  turnsheet 


HOISTING,  LOWERING,  TRANSPORTING 


333 


and  hooks  on  the  loose  end  of  the  go-devil  rope;  he  pushes  it  carefully 
over  the  edge  on  the  track  and  grabs  the  brake  handle,  the  empty  car 
at  the  dump  is  jerked  back  so  that  its  rear  wheels  are  again  on  the  rail 
and  as  the  full  car  descends,  the  empty  one  is  pulled  up.  The  length 
of  the  rope  is  adjusted  so  that,  as  the  full  car  reaches  the  dump  and 
empties,  the  empty  car  is  landed  on  the  turnsheet,  whence  it  is  trammed 
out  on  the  lateral  tracks  for  loading  again. 

The  incline  plane  itself  is  kept  on  as  uniform  a  grade  as  is  convenient. 
It  is  built  of  4  X  6-in.  crossties,  about  8  ft.  long,  spaced  3  ft. ;  these  are 


/if. 

GO-DEVIL  TRACK  OVER  LOW  SPOT 
PIG.    262. ARRANGEMENT   OP    GRAVITY    PLANE    AND    DUMPING    DEVICE. 


held  apart  by  studdles  of  the  same  material  laid  on  1  X  6-in.  boards; 
the  boards  give  no  support  and  are  used  merely  for  lining  in  and  getting 
grade.  The  ties  themselves  are  supported  either  on  the  foot- wall  or  on 
filling,  or  on  poles  across  low  places.  Four  12-lb.  rails  are  spiked  to  the 
ties,  so  as  to  give  a  double  track  from  top  to  bottom  with  20-in.  gage  and 
12-in.  clearance.  The  general  arrangement  is  illustrated  in  Fig.  262. 
Improvement  in  Underground  Trolley  Conveyors  (By  E.  M.  Weston). 
— One  defect  of  the  aerial  rope  automatic  bucket  conveyors  in  use  in 
inclined  stopes  on  the  Rand  is  that  unless  the  haulage  ropes  be  wound 
on  separate  clutched  drums  and  have  power  devices  to  wind  and  unwind 
and  thus  shorten  or  lengthen  the  ropes,  the  buckets  can  load  from  one 


334  DETAILS  OF  PRACTICAL  MINING 

place  in  the  stope  only.  To  avoid  this,  Herbert  Krause,  underground 
manager  of  the  New  Kleinfontein  mine,  invented  the  conveyor  shown  in 
Fig.  263.  It  is  really  an  adaptation  of  the  Whiting  hoist  principle  under- 
ground, and  is  not  patented.  The  illustration  explains  itself.  X  and 
Y  are  the  main  ropes  stretched  parallel  from  top  to  bottom  of  the  slope. 
Z  is  a  swinging  stop  block  to  take  up  any  shock.  M  and  N  are  two  side- 
tipping,  long,  shallow  trucks  of  any  convenient  size,  usually  4  to  10  cu. 
ft.  capacity.  The  haulage  rope  passes  around  the  two  grooved  truck 
wheels  W,  and  over  a  pulley  A ,  which  is  made  to  traverse  along  another 
rope  BC,  so  that  the  working  length  of  the  haulage  rope  in  the  stope  is 
varied.  This  gear  can  work  in  a  stope  as  low  as  45  in.  and  on  a  dip  of 
15°  to  35°. 


FIG.    263. ADJUSTABLE    OVERHEAD    GRAVITY    STOPE    TRAM. 

Hoisting  over  a  Summit  (By  Frank  C.  Rork). — The  scheme  here 
described  was  devised  to  hoist  and  transport  ore  from  a  deposit  in  the 
Moose  Mountain  mine,  over  a  high  point,  to  the  mill  bins  situated  about 
1500  ft.  from  the  ore.  A  headframe  about  20  ft.  high  was  erected  at  the 
highest  point  between  the  ore  and  the  bins.  Instead  of  fastening  the 
sheave  in  the  usual  way,  it  was  suspended  so  as  to  swing  and  turn  accord- 
ing to  the  pull  on  the  cable.  The  bail  on  the  skip  was  constructed  so  that 
it  would  turn  over  as  the  car  went  by  the  headframe.  In  the  position  A, 
Fig.  264,  the  skip  is  shown  coming  up  the  incline.  At  B,  the  momentum 
carries  it  by  the  highest  point  of  the  track,  the  bail  turning  over  as  it 
passes.  The  hoistman  then  releases  the  friction  and  allows  the  loaded 
skip  to  pull  the  cable  out  as  it  goes  down  the  incline  to  the  bins.  It  is 
necessary  to  support  the  cable  on  wooden  rollers,  otherwise  the  drag  of 
the  cable  would  stop  the  skip.  On  the  return  trip,  the  momentum  of 
the  empty  skip  is  sufficient  to  carry  it  past  in  the  same  manner.  By 
speeding  the  hoist  on  the  return  trip  the  round  trip  can  be  made  in  about 
four  minutes,  which  would  limit  the  capacity  to  300  tons  per  10-hr,  shift, 
but  there  is  no  reason  why  4-  or  6-ton  skips  could  not  be  used. 

The  hoist  is  belt-driven  from  a  motor  (not  steam  driven  as  shown  in 


HOISTING,  LOWERING,  TRANSPORTING 


335 


the  illustration).  There  are  two  drive  pulleys  on  the  motor  which  are 
connected  by  two  belts  to  two  pulleys  on  the  hoist  countershaft,  one  60  in. 
and  one  30  in.  in  diameter.  By  means  of  two  friction  clutches  the  30-in. 
pulley  drives  the  hoist  on  the  return  trip  at  double  the  regular  hoisting 
speed. 

Swinging..!, 
Sheave 


Wooden  rollers 
fv  support  cable* 
ab'f.  20  'aparf 


Hoist 

PIG.    264. ARRANGEMENT    FOR    HOISTING    AND    LOWERING. 


SIGNALING 

Evolution  of  an  Electric  Signal  System  (By  George  A.  Packard).— 
The  Raven  mine  at  Butte  was  opened  originally  by  prospectors  and 
leasers  who  very'  properly  followed  the  vein  on  its  dip  with  their  shaft. 
Later  operators  continued  this  shaft  and  made  so  many  changes  in  the 
angle  of  inclination  that  it  became  difficult  to  maintain  and  operate  the 
ordinary  type  of  bell-rope  signal.  Accordingly  it  was  decided  to  install 
electric  lights  at  the  stations,  using  an  alternating  current  of  110  volts, 
and  at  the  same  time  to  add  a  third  wire  and  use  an  electric  bell  in  the 
hoist  room,  the  bell  to  be  rung  by  a  simple  push-button  at  each  station. 
This  worked  satisfactorily  until  the  shaft  entered  wet  ground ;  water  then 
trickled  down  the  wires  and  got  into  the  push-buttons,  resulting  in  stray 


336 


DETAILS  OF  PRACTICAL  MINING 


bells  in  the  engine  room  and  confusion  to  the  men  hoisting  in  the  shaft. 
A  new  management  soon  replaced  the  push-buttons  on  the  wet  levels 
with  "pull-boxes."  This  was  developed  from  one  in  use  at  the  Original 
mine,  and  in  its  present  form  is  shown  in  1  and  2,  Fig.  265.  Changes 


€ 


4%-— -> 


oB 


1.    COVER    BOX 


3.     LAYOUT 
PIG.    265. PULL-BOX,    BUZZER    AND    LAYOUT    FOR    ELECTRIC    SIGNALING. 

were  made  to  eliminate  machine-shop  labor  and  to  remove  the  opportunity 
for  stray  bells  as  the  box  wore. 

It  consists  of  a  plain  cast-iron  cover,  1,  open  only  at  the  bottom  to 
receive  the  fittings  shown  in  2.  The  cover  weighs  9  lb.,  and  is  heavy 
enough  to  stand  the  blow  of  any  small  rock  falling  down  the  shaft.  It  is 


HOISTING,  LOWERING,   TRANSPORTING  337 

fastened  to  the  shaft  timbers  by  long  screws  or  spikes  through  holes  in 
the  three  lugs,  and  has  two  holes  B  for  holding  by  screws  the  wooden 
block  C,  which  plugs  the  bottom  and  acts  as  a  base  for  the  fittings.  This 
block  is  made  small  enough  to  allow  for  swelling;  it  is  bored  vertically 
%  in.  from  the  front  to  admit  the  cylindrical  portion  of  a  mushroom- 
shaped  casting  D  fastened  to  the  block  bottom  with  screws.  This 
cylinder  serves  as  a  guide  for  a  %-m.  eye-bolt  E.  On  the  upper  end  of 
this  bolt  a  small  wooden  block  F  is  held  by  a  nut  which  presses  against 
the  top  of  the  box,  being  forced  up  by  the  spring  H.  The  spring  is  made 
from  No.  12  wire;  its  bottom  rests  against  the  top  of  the  casting  D  in  a 
socket  in  C.  To  the  back  of  the  block  F  is  screwed  a  strip  of  Jf  g-in. 
brass  7,  and  at  each  side  of  C  are  fastened  four  similar  strips  J,  the  back 
two  beveled  back  at  the  top,  and  the  front  two  bent  forward.  The 
back  strips  are  bent  out  at  right  angles  at  the  bottom  and  the  line  wires 
M  and  TV' are  connected,  one  on  each  side,  by  screws.  The  front  brasses 
are  held  in  place  by  the  screw  K,  provided  with  a  washer  and  a  small 
coiled  spring  L,  J£  m-  long.  When  the  bolt  E  is  pulled  down,  the  brass  7 
is  forced  between  the  two  portions  of  the  brasses  J,  making  contact  and, 
by  connecting  M  and  TV,  ringing  the  bell.  The  wires  enter  the  box 
through  two  holes  C,  bored  of  such  size  that  the  insulation  fits  tightly, 
and  so  placed  that  there  can  be  no  possible  contact  with  the  screws  at 
B  or  the  casting  D.  Where  there  is  much  "copper  water"  this  casting 
is  of  brass.  To  prevent  7  from  being  pulled  down  so  far  as  to  stick,  two 
stops  were  subsequently  screwed  into  the  bottom  part  of  (7,  between  E 
and  /,  projecting  about  an  inch  above  the  lower  part  of  C.  /These  are 
not  shown  in  the  illustration.  A  cord  through  the  eye  of  the  bolt,  ending 
in  a  porcelain  knob,  completes  the  device. 

Later,  another  manager,  finding  that  occasionally  a  man,  ringing  for 
air,  say,  on  the  1100,  had  no  way  of  knowing  that  another  man  was 
ringing  to  be  hoisted  from  the  500  at  the  same  moment,  while  the  engineer 
could  not  determine  what  either  was  after,  introduced  a  flash  light  into 
the  circuit  at  each  station.  In  3  is  shown  the  arrangement  at  this  stage. 
Wires  M  and  0  are  those  in  use  for  the  lighting  circuit.  The  wire  N  is 
added  for  the  electric  signal  system,  connecting  with  P,  the  bell  in  the 
engine  room.  This  bell  is  of  the  solenoid  type,  only  one  blow  being 
struck  each  time  the  button  is  pushed.  The  station  light  is  represented 
by  R,  and  the  push-button  used  on  the  dry  level,  by  S.  When  pressed, 
S  closes  the  circuit  between  N,  otherwise  dead,  and  M,  and  rings  the  bell. 
A  pull-box  is  shown  at  T  similarly  placed  on  the  lower  levels.  The  signal 
lights  on  each  station  are  represented  by  U  connected  between  N  and  O, 
so  as  to  glow  only  when  N  is  live.  These  lights  were  only  10- watt  lamps 
and  the  labor  of  connecting  was  small.  The  scheme  eliminated  inter- 
fering signals  and  worked  satisfactorily  until  an  accident  to  a  skip-tender 
22 


338  DETAILS  OF  PRACTICAL  MINING 

showed  that  a  simple  flash  light  was  not  satisfactory,  as  it  was  a  warning 
only  when  watched.  Accordingly,  a  loud  buzzer,  obtained  from  the 
Anaconda  company,  was  substituted,  being  connected  into  the  water- 
proof lamp  socket. 

This  buzzer,  shown  in  4,  consists  of  a  piece  of  board  a,  8  in.  square, 
to  which  is  screwed  a  piece  of  No.  10  sheet  iron  b,  4  in.  wide,  and  7  in. 
long,  the  top  2^  in.  being  bent  out  at  right  angles  to  form  a  shelf.  Be- 
neath this  are  fastened  two  magnets  c  about  2  in.  long,  wound  for  110 
volts.  These  take  about  450  ft.  of  No.  28  wire  each.  The  vibrating 
member  is  a  piece  of  No.  20  galvanized  iron  d,  3%  in.  wide  by  4  in.  long, 
the  top  2^2  in.  being  bent  over  at  right  angles.  This  is  fastened  to  the 
board  through  slots  e  so  that  the  position  may  be  adjusted,  the  horizontal 
portion  being  about  Jf  6  m-  below  the  coils.  It  is  planned  to  vibrate  with 
from  1%  to  2  amp.  The  whole  is  covered  with  a  sheet-iron  cover  to 
keep  it  dry.  The  sound  can  readily  be  heard  in  the  shaft  100  ft.  away. 

The  installation  of  the  buzzers  led  to  some  trouble  with  the  electric 
bell  in  the  engine  room,  as  the  coils  here  were  wound  for  4  amp.,  but  as 
soon  as  these  were  replaced  by  smaller  coils,  this  trouble  was  overcome. 
At  the  same  time  the  buzzers  were  installed,  a  push-button  was  placed 
in  the  line  near  the  engineer's  stand  so  that  he  could  signal  to  the  levels 
if  desired.  The  possibilty  of  return  signaling  in  this  manner  is  a  most 
useful  and  important  feature  in  a  signal  system  and  one  too  often  neg- 
lected. It  offers  a  means  of  avoiding  mistakes  and  even  accidents. 

The  wire  used  in  the  shaft  was  formerly  No.  10  triple-braid  weather- 
proof, but  this  was  not  satisfactory.  It  seems  to  give  satisfaction  where 
it  has  a  chance  to  dry  out  between  rains,  but  where  constantly  wet  under- 
ground very  soon  begins  to  allow  current  to  leak.  The  insulation  also 
begins  to  come  off  under  a  constant  drip,  after  several  months'  service. 
It  was  replaced  by  double-braid  solid-okonite  wire,  and  when  the  shaft 
was  sunk  double-braid  rubber-covered  wire  was  used.  Both  have  been 
perfectly  satisfactory.  The  wires  are  fastened  to  ordinary  porcelain 
knobs  on  the  hanging  side  of  the  manway,  and  no  ducts  of  any  sort  are 
used  to  protect  them. 

The  only  part  of  the  pull-box  which  cannot  easily  be  made  at  any 
mine  are  the  two  castings.  The  total  cost  of  the  pull-box  at  Butte  is 
about  $5.  The  buzzers  cost  $3.15  each.  The  No.  12  triple-braid  weather- 
proof wire  cost  $1.17  per  100  ft.  when  copper  was  selling  at  17  cts.  per 
pound,  while  the  price  of  the  okonite  covered  is  $3.16  and  the  rubber 
covered  $2.10. 

As  electric  power  is  supplied  to  the  mines  from  a  substation  con- 
nected with  several  generating  plants  the  signal  system  is  rarely  out  of 
commission.  In  a  district  where  the  power  is  liable  to  be  cut  off,  an 
auxiliary  storage  battery  would  be  desirable. 


HOISTING,  LOWERING,  TRANSPORTING 


339 


Simple  Return  Signal  System  (By  H.  R.  Wass). — The  accompanying 
diagram,  Fig.  266,  illustrates  a  homemade  electric  signaling  system 
installed  at  the  Rosiclare  Lead  &  Fluorspar  company's  mines  at  Rosiclare, 
111.  It  is  used  for  signaling  between  the  shaft  station  on  the  ore-hoisting 
level  and  the  hoist  room  on  the  surface.  It  is  simple,  reliable,  and  has 
so  far  proved  efficient,  and  it  was  easily  and  cheaply  installed. 

The  signal  board  in  the  hoist  room  is  about  12  X  18  in.  in  size,  built 
of  hard  pine  and  painted  with  two  coats  of  P.  &  B.  paint.  The  switch- 

220  Y    D.C.  Supply 


Signal  board  in  hoist  room 


Lamp 


Lamp 


H      -  To  Mine  L  ights  Snitch  boand  at  shaft  station 

FIG.    266. LAYOUT    PROVIDING    FOR    RETURN    SIGNALS   BY    ENGINEER. 

board  at  the  shaft  station  is  made  of  the  same  material  and  painted  in 
the  same  manner  and  is  protected  from  dripping  water  by  a  wooden 
canopy.  All  wiring  is  double-braid  rubber-covered  and  is  carried  down 
the  shaft,  on  the  mine  level  and  in  the  shaft  station,  in  metal  conduit 
and  is  fully  protected  from  mechanical  injury. 

The  method  of  operation  is  as  follows:  To  hoist,  the  eager  closes  the 
switch  SI,  a  single-pole,  single-throw,  knife  switch,  and  holds  it  closed 


340  DETAILS  OF  PRACTICAL  MINING 

for  two  or  three  seconds;  this  lights  the  lamps  A  and  rings  the  bell  in 
the  hoist  room.  Two  of  the  lamps  A  are  in  series  with  the  bell  to  fur- 
nish the  necessary  resistance.  The  hoisting  engineer  responds  by  pulling 
down  on  E,  which  closes  the  switch  S2,  also  a  single-pole,  single-throw, 
knife  switch,  which  is  held  open  normally  by  the  spring;  this  operation 
causes  the  lamps  marked  C  to  light  up  and  remain  lighted  until  the  spring 
pulls  the  switch  open.  Two  of  these  lamps  are  on  the  switchboard 
in  the  shaft  station  and  the  other  is  located  conveniently  to  the  engi- 
neer's operating  platform  so  that  he  may  observe  whether  or  not  the 
eager  receives  his  return  signal.  All  of  the  signals  are  repeated  by  the 
hoisting  engineer  after  the  underground  signals  are  received  by  him  and 
all  misunderstanding  of  signals  is  thus  avoided.  D  is  a  simple  bell  crank 
forged  from  J^  X  1-in.  bar  and  connected  to  the  handle  of  the  switch 
by  a  small  rope.  The  switch  is  mounted  on  a  wooden  frame  as  shown, 
or  may  be  placed  in  any  other  convenient  position. 

At  F  and  Fl  are  5-amp.  fuses.  Whenever  the  engineer  or  electrician 
wishes  to  test  or  adjust  the  bells,  he  simply  removes  the  fuse  from  F19 
places  it  in  the  socket  at  F2  and  closes  the  switch  S  which  rings  the  bell 
and  lights  the  lamps  A  on  the  hoist-room  switchboard.  All  lamps  are 
carbon  filament,  50- watt,  220-volt  lamps  working  on  a  220-volt  direct 
current.  The  bell  is  of  a  weatherproof  ironclad  type,  wound  to  a  re- 
sistance of  30  ohms;  it  consumes  0.3  amp.  of  current. 

Electric  Signal  System,  Argonaut  Mine  (By  R.  S.  Rainsford). — 
The  electric  signal  apparatus  here  described  was  devised  to  meet  the 
following  requirements:  (1)  To  be  available  from  a  moving  skip  or  cage, 
as  well  as  from  a  station  platform;  (2)  to  be  easily  rung,  as  by  a  light 
pull  on  the  bell  signal  cord;  (3)  to  be  absolutely  reliable,  even  if  por- 
tions of  the  signal  cord  in  the  shaft  were  broken ;  (4)  to  register  one  stroke 
of  the  electric  bell  for  each  tug  on  the  cord.  For  reasons  to  be  explained 
this  last  requirement  is  the  crux  of  the  whole  problem. 

The  great  depth  of  the  Argonaut  shaft,  and  the  fact  that  it  is  an  in- 
cline (60°)  made  the  ringing  of  signals  by  the  ordinary  bell  cord  a  difficult 
task.  For,  despite  the  addition  of  long  hand  levers  for  ringing  and  the 
supporting  of  the  signal  cord  at  intervals  by  sensitive  S-shaped  springs, 
together  with  the  greasing  of  all  cleats  guiding  the  cord  and  constant 
supervision  of  the  line,  the  system  was  anything  but  satisfactory.  Con- 
sequently when  telephones  were  introduced  in  the  mine  a  few  years  ago 
a  four-wire  cable  was  laid  in  the  shaft,  two  of  the  wires  being  used  for 
the  telephone  circuit  and  two  for  a  system  of  electric  push-buttons 
situated  at  all  stations  and  loading  chutes  in  the  shaft.  These  push-but- 
tons, greatly  modified  in  design,  are  still  in  use,  but  have  the  great  dis- 
advantage that  they  are  not  available  from  a  moving  skip. 

The  most  common  method  of  meeting  the  first  requirement  above 


HOISTING,  LOWERING,  TRANSPORTING  341 

mentioned,  namely,  two  naked  wires  strung  in  each  hoisting  compart- 
ment about  4  in.  apart,  and  charged  with  current  of  exceedingly  low 
potential,  is  usually  unsatisfactory  and  dangerous.  To  ring  a  bell 
one  has  only  to  short-circuit  the  two  wires  with  any  convenient  piece  of 
metal,  as  a  candlestick.  But  two  objections  present  themselves.  One 
is  the  rapid  eating  away  of  any  uninsulated  wires,  whether  galvanized 
iron  or  copper,  when  subjected  to  the  mine  waters  and  atmosphere  of 
certain  mines.  The  other  is  the  danger  of  a  signal  given  by  mistake 
through  contact  with  the  wires  by  any  tool  in  the  hands  of  a  miner  re- 
pairing the  shaft,  particularly  a  bar  when  the  skip  tender  is  barring  a 
loading  chute  in  the  shaft. 

Another  system  was  tried  which  included  bonding  the  shaft  rail  for 
one  leg  of  the  current,  insulating  the  skip  and  using  the  hoisting  cable  for 
the  other  leg  or  conductor,  together  with  a  signaling  device  on  the  skip 
to  make  or  break  the  circuit.  This  system  proved  exceedingly  trouble- 
some, either  on  closed  or  open  circuit,  and  was  finally  abandoned.  The 
only  solution  remaining  therefore  was  some  yet  undetermined  method 
involving  a  more  sensitive  signal  cord  in  connection,  with  the  electric 
gong  of  the  push-button  system  and  its  cable. 

To  make  the  signal  cord  sensitive  was  an  easy  matter.  It  was  cut 
in  500-ft.  sections,  the  bottom  of  each  section  fastened  to  a  divider  of 
the  shaft  sets,  the  top  of  each  section  supported  by  an  S-spring,  as  shown 
at  F  in  4,  Fig.  267,  and  the  signal  cord  guided  by  cleats  in  the  usual  way. 
Then  a  bell  crank,  with  8-in.  arms,  was  connected  to  the  signal  cord  below 
the  S-spring  and  its  free  upper  arm  used  through  an  appropriate  device 
to  register  every  pull  on  the  signal  cord.  A  signal  cord  has  one  peculiarity 
— all  pulls  on  it  are  not  of  equal  strength.  One  may  easily  arrange  an 
electric  contact  which  will  be  made  or  broken,  depending  on  whether  open 
or  closed  circuit  is  used,  by  a  light  tug  on  the  cord.  The  problem  is  to 
prevent  a  double  signal  if  this  sensitive  cord  is  pulled  so  hard  that  the 
contact  is  passed  and  the  mechanism  must  retrace  its  steps  and  again 
pass  the  ringing  contact  as  the  signal  cord  is  released.  If  a  long  sliding 
contact  is  used  to  meet  this  difficulty  the  electro-mechanical  gong  at  the 
surface  may  have  time  to  ring  twice  before  the  contact  is  broken.  The 
solution  in  the  case  of  the  signal  device  to  be  described  is  to  jump  the 
contact  on  the  return  stroke,  or  release  of  the  signal  cord. 

Thus  a  light  pull  on  the  signal  cord  drives  the  lifting  member  S, 
1  and  2,  Fig.  267,  under  the  lifter  pin  R  and  so  closes  the  contacts  Q 
and  0  by  raising  R  and  the  spring  P.  On  the  release  of  the  signal  cord, 
S  drops  back  to  its  normal  position  in  front  of  the  stop  or  guide  Y. 
A  heavier  pull,  however,  drives  S  under  R  and  out  beyond,  thus  both  mak- 
ing and  breaking  the  contact  at  Q  and  0,  but  on  the  release  of  the  signal 
cord  S,  which  has  a  laterally  projecting  portion  beveled  on  the  under 


342 


DETAILS  OF  PRACTICAL  MINING 


side  as  well  as  on  the  top,  as  shown  in  3,  slides  over  instead  of  under  R 
and  so  makes  no  contact  on  the  return  stroke. 

The  rest  of  the  apparatus  is  easily  understood  from  the  figures,  in 
which  K  is  a  wooden  base,  L  a  slate  slab,  Z  brass  connectors  with  binding 
posts  N  for  the  wire  terminals  M  of  the  electric  circuit.  On  the  two 
brass  connectors  are  mounted  the  springs  0  and  P,  the  latter  supporting 
also  the  contact  point  Q  and  the  lifter  pin  R.  A  bracket  W  supports  the 
pin  R  at  the  proper  elevation,  while  another  bracket  X  serves  as  a  guide 
and  backstop  Y  for  the  lifting  member  S.  The  latter  is  fitted  with  the 


~v~ 

—  I 

r~i 

I 

\ 

_®. 

<? 

£ 

r 

v 

NS 

df     d) 

X 

t,-P 

w 

0                N-v. 

^               dD      ® 

^^f* 

v 

rf=Ti 

Z"Y- 

J 

1     si 

III 

J 

M 

lU^d) 

T         <D 

FIG.    267. LAYOUT    AND    CIRCUIT    CLOSER    FOR    COMBINATION    CORD-ELECTRIC    SIGNAL 

SYSTEM    AT    ARGONAUT    MINE. 

stud  U  running  in  the  guide  T.  To  the  stud  is  fastened  the  link  or  rod 
V  leading  to  the  upper  arm  of  the  bell  crank  /  through  the  insulating 
block  J. 

The  device  is  applicable  to  any  shaft  whether  vertical  or  inclined, 
and  if  any  section  of  the  signal  cord  should  break,  or  any  individual 
circuit  closer  be  damaged,  signals  in  other  sections  of  the  shaft  are  not 
interfered  with.  In  practice,  moreover,  it  is  found  that  a  signal  can 
easily  be  rung  from  a  fast-moving  skip  by  giving  the  signal  cord  a  jerk 
with  only  one  or  two  fingers. 

Bare -wire  Electric  Signal  System  (Bull.\  American  Institute  of 
Mining  Engineers). — The  Penn  Iron  Mining  Co.  in  Michigan  uses  a 


HOISTING,  LOWERING,  TRANSPORTING 


343 


rather  unusual  system  of  electric  signaling.  An  alternating  current  of 
110  volts  taken  from  the  lighting  system  is  reduced  to  30  volts  through  a 
small  transformer.  This  30-volt  circuit  is  used  to  ring  what  is  called  a 
grade  bell,  i.e.,  a  signal  to  indicate  the  class  of  ore  hoisted,  and  also  to 
operate  two  relays,  one  of  which  rings  the  skip  bell  in  the  hoist  house  by 
closing  a  100- volt  circuit,  while  the  other  similarly  rings  the  cage  bell. " 
One  side  of  the  30-volt  circuit  is  grounded,  the  other  connected  to  the 
grade  bell  and  the  relays  as  shown  in  Fig.  268.  The  other  sides  of  the 
grade  bell  and  the  relays  are  connected  to  No.  4  bare  copper  wires  sup- 
ported on  insulators  down  the  shaft.  By  grounding  any  one  of  these 
copper  wires,  a  current  will  flow  through  the  grade  bell  or  a  relay  and 
give  a  signal.  The  bell  wire  for  the  cage  is  near  the  center  of  one  side  of 
the  compartment  so  that  it  is  almost  impossible  to  reach  and  ring  it  unless 
one  stands  on  the  cage.  This  prevents  ringing  the  cage  bell  when  the 


Skip  Bell  Cage  dell  ^Oround 


Grade    5kip      Cage 
Bare  Shaft  Wires 


FIG.    268. CONNECTIONS    FOR    RELAY    AND    DIRECT    SIGNALING. 

cage  is  not  in  sight,  such  ringing  being  a  frequent  source  of  accidents. 
A  short  piece  of  flexible  wire  with  a  piece  of  bare  No.  4  wire  on  its  end  is 
fastened  to  the  iron  work  of  the  cage  so  that  the  shaft  signal  wire  can  be 
grounded  from  any  point  in  the  shaft,  whether  the  cage  be  moving  or  at 
rest.  The  skip  and  cage  bells  are  16  in.  in  diameter  and  are  set  in  a  local 
110- volt  circuit,  which  is  closed  and  opened  by  the  relays  mentioned. 
The  blow  on  the  gong  is  struck  by  a  bar  in  a  heavy  solenoid.  An  in- 
dicator which  registers  the  number  of  bells  rung  is  also  actuated  and  a 
lamp  is  lighted. 

Gravity -release  Electric  Signal  Box  (By  W.  R.  Hodge). — An  electric- 
contact  signal  box  which  has  proved  satisfactory  through  several  years 
of  hard  service  is  shown  in  Fig.  269.  The  device  consists  of  a  fixed 
block  nailed  to  the  top  of  an  inclosing  box  and  a  movable  handle  extend- 
ing through  the  end  of  the  box.  The  block  and  handle  are  connected 
by  a  butt  hinge.  Brass  plates  for  making  contact  are  screwed  to  both  the 
block  and  the  handle.  Soldered  to  the  side  of  each  brass  plate  is  a  wire 


344 


DETAILS  OF  PRACTICAL  MINING 


connecting  with  the  bell  line.  The  handle  must  be  lifted  to  make  a  con- 
tact and  give  a  signal.  The  contact  made,  the  handle  naturally  drops  to 
the  open  position  without  further  attention.  Ordinarily  the  boxes  are 
unpainted  but  in  unusually  wet  places  a  coat  of  paint  and  a  shield  which 
moves  with  the  handle  and  covers  the  handle  opening  into  the  box,  make 
for  increased  efficiency.  These  boxes  have  worked  well  in  wet  stations. 
Locked  Signal  System  (By  H.  H.  Hodgkinson). — The  signal  system 
installed  in  the  Palmer  shaft  of  the  New  Jersey  Zinc  Co.'s  mine  at  Frank- 
lin, N.  J.,  by  R.  M.  Catlin  and  designed  by  L.  G.  Rowland  is  unique 
and  has  many  decided  advantages  over  other  signal  devices.  A  signal 
box  is  located  at  each  shaft  station  and  is  operated  by  a  lever  on  the 
side,  to  which  is  attached  a  short  chain  and  handle  to  facilitate  pulling 
the  lever.  The  cage,  however,  is  moved  only  on  signal  given  to  the  engi- 
neer by  a  man  who  carries  a  key  to  the  device  and  who  travels  with  the 
cage.  The  signal  boxes  are  situated  at  each  station  in  such  a  position 


Porcelain 
Insulators 


JL. 


FIG.    269. CONTACT   IN   BOX,    CLOSED   BY    LIFTING    HANDLE. 

as  to  be  easily  accessible  to  the  cage  conductor  and  enable  him  to  see  his 
cage  constantly,  thus  minimizing  the  danger  of  mishaps  from  the  cage 
moving  while  men  are  getting  on  or  off. 

In  operating,  the  pull  and  release  of  the  lever  ring  the  gongs  in  all 
other  signal  boxes,  but  do  not  ring  the  engineer.  Thus  it  is  always 
possible  to  signal  for  the  cage  from  any  station  in  the  shaft  and  to  notify 
anyone  about  to  ring  a  signal  from  any  other  station  that  there  is  al- 
ready a  signal  being  rung,  thus  preventing  confusion.  As  soon  as  the  cage 
conductor  receives  a  signal — provided  there  is  nothing  to  prevent  him 
from  bringing  the  cage  to  the  station  from  which  the  signal  was  rung — 
he  inserts  a  special  key  in  the  lock  on  the  front  of  the  box  and  turns  it, 
thus  connecting  the  one  signal  box  with  the  engineer's  signal  in  the 
engine  house.  He  then  signals  the  engineer  by  means  of  the  requisite 
number  of  pulls  on  the  lever;  this  signal  at  the  same  time  rings  at  each 
station,  notifying  the  persons  who  rang  the  original  signal  that  the  cage 
is  coming.  The  conductor  remains  at  the  signal  box  with  his  .key  in  the 


HOISTING,  LOWERING,  TRANSPORTING 


345 


lock  waiting  for  the  engineer  to  repeat  his  signal.  If  the  engineer  repeats 
correctly,  the  conductor  removes  his  key,  climbs  on  the  cage  and  proceeds 
to  the  station  signaling.  If,  however,  the  signal  rung  back  by  the  engi- 
neer happens  to  be  wrong,  the  conductor  rings  one  bell  to  the  engineer 
to  stop  and  the  exchange  of  signals  is  repeated.  There  is  always  am- 
ple time  allowed  the  cage  man  to  remove  the  key  and  climb  on  the  cage. 
Fig.  270  shows  a  diagram  of  the  system.  This  consists  of  the  two 
circuits  Y  and  X.  Through  circuit  X  there  is  a  constant  current  flowing 
which  causes  the  electro-magnets  to  operate  the  clappers  of  the  gongs 
in  the  signal  boxes  when  the  pull  switch  is  thrown.  It  will  be  seen  that 


STAJfON  No.  I 


tl' 


Hey  Switch 


KeySwitch 
STATION  No.S 


IK 

KeySwitch 
STATION  No.  3 

FIG.    270. DIAGRAM    OF    SYSTEM    AND    FRONT    OF    SIGNAL   BOX. 

this  operation  does  not  operate  the  engineer's  signal.  Through  the 
circuit  Y  there  is  no  current,  and  when  the  key  switch  is  thrown  the  signal 
box  is  merely  connected  to  the  engineer's  signal,  which  cannot  ring  until 
the  pull  switch  is  also  thrown,  causing  the  current  to  pass  through  circuit 
Y  and  operate  the  engineer's  signal. 

The  signal  boxes  are  constructed  of  cast  iron  as  shown.  The  front 
of  the  signal  box,  Fig.  270,  is  in  the  form  of  a  door  to  permit  repairs  to 
be  made  inside.  It  is  locked  by  means  of  the  same  key  which  operates 
the  engineer's  signal,  in  addition  to  being  fastened  by  a  screw  in  each 
corner.  The  doors  are  fitted  on  the  inside  with  a  §^-in.  round-rubber 


346 


DETAILS  OF  PRACTICAL  MINING 


HOISTING,  LOWERING,  TRANSPORTING 


347 


348  DETAILS  OF  PRACTICAL  MINING 

gasket  to  prevent  water  from  getting  into  the  boxes.  The  locks  are  so 
constructed  that  it  is  impossible  to  remove  the  key  and  leave  the  key 
switch  thrown  and  the  signal  box  connected  to  the  engineer's  signal. 
On  the  door  of  the  signal  box  an  emergency  signal  device  is  placed  so 
that  the  cage  can  be  stopped  immediately  in  case  of  an  actual  or  threat- 
ened accident.  This  consists  of  a  brass  pin  held  in  place  by  a  round 
piece  of  window  glass,  which  when  broken  permits  the  pin  to  be  forced 
outward  by  means  of  a  spring,  making  the  same  connection  as  the  key 
switch  would.  The  lever  is  then  pulled  once,  which  will  bring  the  cage 
or  skip  to  a  stop  if  in  motion.  The  gong  is  placed  on  top  of  the  signal 
box  proper  and  over  it  is  bolted  a  tightly  fitting  cast-iron  cover,  which 
prevents  any  water  from  working  its  way  inside.  The  cover  has  a 
J^-in.  slot  on  the  front  and  sides  to  enable  one  to  hear  the  gong  more 
distinctly. 

The  lever  A,  Figs.  271  and  272,  which  operates  the  pull  switch  is 
situated  on  the  outside  of  the  box  and  has  its  movement  confined  to  the 
space  between  the  two  lugs  L  L  to  prevent  any  injury  to  the  switches 
inside.  The  pull-switch  lever  C,  in  the  position  shown  in  Fig.  271,  per- 
mits the  current  to  pass  to  the  electro-magnet  which  holds  the  clapper 
up  against  the  gong.  When  the  lever  A  is  pulled  down,  the  lever  C 
assumes  the  position  shown  by  the  dotted  lines,  which  breaks  the  cir- 
cuit X,  causing  the  clapper  to  drop  and  at  the  same  time  closes  the 
circuit  Yj  when  the  key  switch  K  is  thrown,  and  thus  rings  the  en- 
gineer's signal.  Upon  releasing  the  lever  A  it  is  returned  to  its  normal 
position  by  the  spring  S,  Fig.  272,  the  circuit  X  is  closed  again,  causing 
the  clapper  to  strike  the  gong,  and  the  circuit  Y  is  broken  as  before. 
The  spring  S  is  fastened  to  the  short  lever  B,  which  operates  the  shafting 
E,  to  which  the  lever  A  and  the  switch  lever  C  are  attached. 

Bell-wire  Arrangement  in  Sinking  (By  Clinton  P.  Bernard). — In 
shaft  sinking  it  is  necessary  to  carry  down  the  signal-bell  wire  or  rope  as 
depth  is  gained.  In  shafts  over  200  to  300  ft.  deep,  it  is  common  to  use 
a  heavy  wire  or  wire  rope  from  the  surface  to  a  point  about  50  ft.  from 
the  bottom,  and  a  rope  for  the  rest  of  the  way.  There  are  numerous 
ways  of  arranging  the  wire  and  bell  at  the  surface,  but  the  one  shown 
in  Fig.  273  is  simple  and  has  many  advantages.  The  wire  is  wrapped 
three  or  four  times  over  a  wooden  spool  attached  to  the  post  of  the 
headframe,  then  passed  through  the  handle  of  the  weight  cylinder,  lashed, 
and  the  rest  of  the  coil  hung  in  some  convenient  place.  The  weight 
cylinder  is  a  piece  of  2J^-in.  pipe  with  a  cap  on  the  bottom,  filled  with 
scrap  to  give  the  desired  counterweight.  This  weight  cylinder  moves 
in  a  4-in.  pipe  outside  the  collar  set  and  extending,  for  convenience, 
about  3  ft.  above  the  ground.  A  bumper  on  the  spool  permits  it  to 
revolve  just  enough  to  actuate  the  bell  through  a  wire  fastened  to. an  arm 


HOISTING,  LOWERING,  TRANSPORTING 


349 


on  the  spool.  The  shaft  wire  may  be  lengthened  as  desired,  by  un- 
fastening the  lashing  above  the  weight  cylinder,  and  allowing  the  required 
length  of  wire  to  slip  over  the  spool,  thus  doing  away  with  splicing.  No 
springs  are  required  and  there  are  no  weights  to  dislodge  and  fall  into 
the  shaft.  By  adjusting  the  counterweight,  the  pull  on  the  wire  need 
be  but  a  few  pounds  through  3  or  4  in.  The  entire  outfit  can  be  made 
in  a  short  time,  at  small  expense. 


FIG.    273. ARRANGEMENT   OF    SIGNAL    PULL-WIRE    AT   SHAFT   COLLAR. 

Warning  Bell  for  Topman  (By  Harold  A.  Linke). — At  many  small 
shafts  the  "topman,"  besides  acting  as  skip  tender  and  car  "  rustler," 
is  engaged  in  making  ladders  or  striking  for  the  blacksmith,  etc.  These 
odd  jobs  take  him  away  from  the  shaft,  and  even  though  he  be  exceed- 
ingly careful  and  conscientious,  he  is  likely  to  miss  a  bucket  occasionally. 
As  the  rule  is  not  to  delay  shaft  work,  any  contrivance  which  tends  to 
obviate  such  delay  makes  for  efficiency.  Fig.  274  shows  a  simple  device 
for  completing  an  electric-bell  circuit,  for  use  on  the  indicator  of  the  hoist. 
A  depth-  or  station-marker,  furnished  with  the  indicator,  can  be  fastened 
at  the  position  desired  by  means  of  a  setscrew.  A  piece  of  galvanized 
iron  is  bent  as  shown  and  punched  with  a  hole  large  enough  to  pass  the 
setscrew  without  contact.  Two  mica  insulators,  such  as  are  furnished 
with  ignitors  of  gas  engines,  or  thin  rubber  gaskets  are  used  to  set  the 


350 


DETAILS  OF  PRACTICAL  MINING 


galvanized  iron  off  from  the  setscrew  and  the  marker.  A  cut  metal 
washer  is  applied  as  shown.  A  copper  wire  to  the  bell  is  soldered  to  the 
galvanized  iron ;  the  other  wire  may  be  grounded  or  fastened  to  some  part 
of  the  engine,  such  as  a  screw  of  the  name  plate.  The  marker  is  set  at 
some  point  on  the  indicator  so  that,  in  hoisting,  the  contact  between  the 
movable  pointer  and  the  piece  of  galvanized  iron  may  be  made,  and  the 
warning  bell  rung  sufficiently  early  for  the  topman  to  be  at  the  shaft 
collar  to  meet  the  ascending  bucket. 


Movable... 
Pointer ' 

Insulator-' 


Depth 
darker 


INDICATOR-- 


/Set-screw 

Ci/fffffa/ 

Washer 


{Depth 

Marker 


Pointer 

Galvanized    ( 
Iron     _  / , 

Insulators 

FIG.    274. DEVICE    FOR    COMPLETING    ELECTRIC    CIRCUIT    OF    WARNING   BELL. 

Automatic  Light  Switch  for  Electric  Tramming  (By  L.  0.  Kellogg). — 
It  frequently  happens  in  underground  electric-haulage  systems  that  the 
main  drift  branches  a  short  distance  from  the  shaft  and  that  loaded 
trains  are  brought  in  over  both  branches.  It  then  becomes  necessary 
to  signal  to  any  incoming  trains  whether  the  track  between  the  junction 
and  the  shaft  is  open  or  whether  a  train  from  the  other  branch  drift  is 
dumping  at  the  pocket.  This  signaling  is  done  automatically  by  colored 
lights  in  a  neat  way  at  the  Oliver  mines  near  Ely,  Minn.  A  switch  is  set 
in  the  back  of  the  drift  so  as  to  be  tripped  by  the  trolley  wheel  of  the  in- 
coming train  and  to  flash  a  red  light.  The  trolley  wheel  of  the  outgoing 
train  usually  flashes  a  green  light.  A  train  approaching  on  the  other 


HOISTING,  LOWERING,   TRANSPORTING 


351 


branch  drift  will  stop  if  the  motorman  sees  a  red  light  and  will  proceed 
if  he  sees  a  green.  It  is  not  entirely  necessary  to  use  the  green  light,  but 
somewhat  safer;  for  if  two  lights  are  used,  the  absence  of  either  a  green 
or  a  red  light  indicates  that  something  is  wrong  with  the  system,  and 
the  motorman  will  not  proceed  as  he  would  if  the  mere  absence  of  a  red 
light  was  used  to  indicate  a  clear  track.  Only  one  switch  is  necessary, 
set  where  it  will  be  operated  by  trains  from  both  drifts.  One  or  two  sets 
of  lights  may  be  used,  only  one  set  being  required  if  a  point  can  be  had 
visible  from  a  sufficient  distance  in  both  drifts;  this  is  sometimes  im- 
possible on  account  of  the  curve  arrangements. 

The  construction  of  the  switch  is  shown  in  Fig.  275.  It  consists  of  a 
wooden  box  inclosing  the  contacts.  A  vertical  pivoted  finger  is  connected 
through  the  bottom  of  the  box  with  two  horizontal  wings  which  the  trolley 
wheel  strikes;  the  finger,  thrown  laterally  by  the  movement  of  the  wings, 


Spring^ 

Brass  plate 

on  cover  4" 

Jong 

Connect  to  rail 
or  trotfeywre 


FIG.    275. SWITCH    TO    SIGNAL    POSITION    OF    UNDERGROUND    MOTOR. 

completes  a  circuit  through  the  lamp  of  the  proper  color.  The  wings 
of  wood  are  shod  with  iron  where  struck  by  the  wheel  and  where  they 
strike  the  bottom  of  the  box,  in  order  to  resist  wear.  The  top  of  the  wing- 
piece  is  shaped  as  an  arc  to  fit  the  opening  in  the  box,  which  is  thus  kept 
closed.  The  box  itself  consists  of  a  wooden  back  and  a  wooden  front 
piece  screwed  together  through  filling  blocks  which  form  the  box  sides. 
The  finger,  by  means  of  the  brass  spring  shown,  maintains  a  constant 
contact  with  a  brass  plate  on  the  inside  of  the  box  front  piece,  which  is 
connected  to  one  side  of  both  lamp  circuits.  The  spring  connects  with 
a  brass  cap  on  the  finger,  and  this  makes  contact  with  one  of  two  fingers 
taken  from  a  motor  controller.  One  of  these  connects  with  the  other  side 
of  the  red-light  circuit,  the  other  with  the  other  side  of  the  green  light. 
In  the  case  shown,  the  trolley  current  is  used  for  the  lights;  if  a  separate 
lighting  circuit  were  in  service,  connections  could  be  as  easily  made  to  this. 


352 


DETAILS  OF  PRACTICAL  MINING 


This  device  is  mounted  on  a  board  fastened  parallel  with  the  tracks 
between  two  caps. 

WINDLASS  AND  WHIM 

Test-pit  Windlass  (By  L.  D.  Davenport). — In  the  openpit  mines  of 
the  Chisholm  district,  on  the  Mesabi  range,  it  is  the  custom  during  the 
winter  season  to  put  down  a  large  number  of  test  pits  in  the  ore  for  ex- 
ploration purposes.  These  pits  are  usually  about  3  X  4  ft.  in  cross- 
section  and  range  in  depth  from  10  ft.  to  80  ft.  Fig.  276  shows  the  de- 
tails of  the  windlass  used  to  hoist  the  ore  from  these  pits.  Four  railroad 
ties  are  placed  around  the  mouth  of  the  test  pit  to  form  a  collar  and  the 
bottom  of  the  windlass  frame  is  spiked  to  this  collar.  The  windlasses 
used  for  underground  test  pits  are  made  on  the  same  general  plan,  except 
that  they  are  smaller. 


Drum,  Round 
Timber  6"Qiam. 
6ft  Long 

*  / 


PIG.    276. A    SIMPLE    HAND    WINDLASS. 

Windlass  for  Single-hand  Sinking  (By  Albert  G.  Wolf).— The 
accompanying  illustrations,  Fig.  277,  show  a  windlass  and  a  self -dumping 
mechanism  with  which  a  prospector  can  sink  a  shaft  alone,  while  saving 
the  labor  of  climbing  in  and  out  of  the  shaft  to  hoist  each  bucket.  The 
windlass  is  small  enough  to  be  placed  at  the  bottom  of  a  shaft  and  light 
enough  to  be  installed,  operated  and  removed  by  one  man. 

The  windlass,  as  shown  in  plan  and  elevations,  consists  of  a  wooden 
drum,  1  ft.  long  by  6  in.  in  diameter,  an  axle  and  crank  made  of  a  single 
piece  of  round  iron,  and  a  yoke  of  round  iron,  which  supports  the  drum 
and  crank.  The  yoke  is  held  by  two  eye-bolts  fastened  through  a  piece 
of  2  X  6-in.  plank.  The  windlass  is  braced  and  prevented  from  swinging 
in  the  eye-bolts  by  a  third  piece  of  round  iron,  one  end  of  which  is  bent 
around  the  axle  at  the  crank  end  of  the  drum,  and  the  other,  hook- 
shaped,  passed  through  a  third  eye-bolt  in  a  horizontal  piece  of  2  X  12- 
in.  plank.  The  two  planks  are  spiked  securely  together.  When  the 
windlass  is  to  be  set  up,  the  vertical  piece  is  placed  at  the  center  of  one 
end  of  the  shaft  and  the  horizontal  piece  is  wedged  firmly  between  the 


HOISTING,  LOWERING,   TRANSPORTING 


353 


two  walls,  just  as  a  stull  would  be.  The  length  of  the  horizontal  piece 
will  be  varied  according  to  the  size  of  the  shaft  being  sunk.  As  the  drum 
is  small,  space  for  extra  cable  is  made  by  driving  two  rows  of  pins,  about 
an  inch  apart,  around  the  drum  near  one  end.  These  pins  are  large  nails 
which  have  the  heads  cut  off. 

The  framework  of  the  dumping  device  is  made  entirely  of  2  X  4-in. 
lumber.  The  bucket  slides  on  two  skids  to  the  top  of  the  shaft.  Here, 
two  lugs,  riveted  to  the  bucket  below  its  center  of  gravity,  engage  two 
outer  skids,  to  which  are  fastened  two  beveled  pieces ;  the  bucket  travels 
up  these  as  on  an  incline  plane.  When  the  top  is  reached,  the  lugs  strike 
two  pivoted  pins  and  drop  over  the  ends  of  the  planks.  By  slacking 


•Wedge 

~&ide   Elevation  End  Elevation     Side  Elevation 

Dumping  Device 

FIG.    277. ONE-MAN    SINKING    LAYOUT. 

the  rope  at  this  point,  the  bucket  is  allowed  to  turn  over  on  its  lugs  and 
dump  its  contents  into  a  chute  properly  placed.  The  bucket  is  then 
hoisted  a  few  inches  over  the  pins,  which  fall  into  place,  and  the  lugs 
guide  the  bucket  over  them  to  the  skids  again.  When  it  is  desired  to 
remove  the  windlass  and  protect  it  from  blasts,  enough  muck  is  placed 
in  the  bucket  to  balance  the  windlass,  and  the  bucket  is  hoisted  to  twice 
the  height  that  it  is  desired  to  raise  the  windlass.  The  hook  brace  is 
then  loosened,  the  drum  is  swung  against  the  frame  and  fastened,  the 
wedges  are  knocked  out  and  the  machine  ascends  without  much  effort 
on  the  part  of  the  operator.  This  machine  was  devised  by  W.  J.  Finney, 
of  Luningf,  Nev. 

23 


354 


DETAILS  OF  PRACTICAL  MINING 


Device  for  Handling  Prospecting  Bucket  (By  Thomas  M.  Smither). — 
The  device  illustrated  in  Fig.  278  is  designed  to  allow  extending  the  dump 
from  a  prospecting  shaft  without  arduous  handling  of  the  bucket.  The 
action  of  the  contrivance  is  apparent  from  the  drawing.  The  hoisted 
bucket  is  released  and  placed  on  the  movable  end  of  the  board,  which  is 
then  revolved  about  its  pivoted  end  by  sliding  on  the  track  A  until 
the  dumping  point  is  reached.  The  fixed  end  of  the  2  X  12-in.  by  14-ft. 
revolving  board  is  bolted  to  a  12  X  12-in.  block  with  washers  inserted  to 
insure  easy  motion..  The  1-in.  round  iron  A  is  an  old  cyanide  tank  hoop. 
It  is  fastened  to  the  supporting  boards  by  nails  on  the  sides,  the  heads  of 
which  are  kept  below  its  top.  Pipe  or  rail  would  answer  the  purpose  as 
well.  The  bottom  of  the  board  was  protected  against  wear  on  the  moving 
end  by  iron  straps.  The  iron  was  greased  and  the  loaded  board  easily 
moved  thereon. 


FIG.    278. PROSPECT  BUCKET    DUMPING    ARRANGEMENT. 

Lowering  in  Balance  through  Timber  Shaft. — In  the  iron  mines  of 
the  Mesabi  range  the  timber  and  boards  used  underground  are  seldom 
handled  in  the  main  hoisting  shafts.  Instead,  one  or  more  timber  shafts 
are  sunk  at  different  points,  affording  ventilation  and  saving  underground 
tramming.  There  are  several  different  styles  of  timber  shaft  ranging 
from  the  inclined  slide  to  the  more  elaborate  type  with  counterweighted 
cage.  Fig.  279  shows  a  simple  headframe  used  on  the  timber  shafts 
of  one  of  the  larger  mines.  The  IJ^-in.  manila  rope  is  passed  five  or  six 
times  around  the  drum  and  made  of  such  a  length  that  one  end  is  at  the 
bottom  of  the  shaft  when  the  other  end  is  at  the  top.  There  is,  therefore, 
no  labor  wasted  in  raising  the  empty  rope  as  there  is  in  most  timber 
shafts.  Two  men  work  together,  one  operating  the  drum  and  the  other 
handling  the  timber  or  boards.  The  headframe  and  drum  are  con- 
structed by  the  mine  carpenter  and  assistants  in  from  two  to  two  and  one- 
half  days.  The  length  of  the  drum  should  be  carefully  determined  in 
proportion  to  the  depth  of  the  shaft  so  as  to  prevent  a  lateral  travel  of 
the  rope  greater  than  the  length  of  the  drum.  One  of  these  headframes 
is  now  being  used  to  lower  timbers  160  ft.,  with  perfect  success. 


HOISTING,  LOWERING,  TRANSPORTING 


355 


Lowering  Windlass  for  Timber  Shaft  (By  L.  D.  Davenport).— 
The  windlass  shown  in  Fig.  280  was  constructed  for  the  purpose  of  lower- 
ing timber  and  other  material  down  a  shaft.  The  drum  is  made  of  a 
piece  of  iron  pipe  14  in.  in  diameter  outside  and  4  ft.  6  in.  long.  This  is 
connected  to  a  2%-in.  square  axle  by  means  of  two  iron  castings,  riveted 
to  the  pipe  with  %-in.  countersunk  rivets.  One  of  these  castings  is 
larger  than  the  other  and  forms  the  brake  wheel  A.  It  is  28  in.  in  diame- 
ter with  a  6-in.  face  and  has  a  2-in.  shoulder  turned  to  fit  the  inside  of 
the  pipe.  The  axle  is  made  of  2^-in.  square  stock  and  is  7  ft.  2  in.  long 
over  all.  The  last  2  in.  on  each  end  B  is  made  1^  in.  square  to  receive 


14  "Pulleys 


—      k-.y/Q'-'-^  W- 7-4-"—  -    >\  Detail  of  Drum 

< --—./£.!  4* ___P 

Plan. 

FIG.    279. WINDLASS    AND    HEADFRAME    FOR    LOWERING    IN   BALANCE. 


cranks  used  for  turning  the  windlass;  the  next  8J^  in.  on  each  end  is 
turned  to  2J^  in.  in  diameter  for  the  bearings,  which  are  2J^  X  7J^  in., 
and  babbitted  ^  in.;  and  5  ft.  5  in.  is  left  in  the  center  of  the  axle  2J^ 
in.  square.  The  brake  band  is  of  %  Q  X  6-in.  iron,  6  ft.  8  in.  long,  and 
is  drilled  with  %6-m-  holes  to  allow  eight  basswood  brake-block  seg- 
ments 2  in.  thick,  to  be  bolted  to  it.  These  basswood  blocks  last  from 
eight  months  to  one  year.  The  ordinary  fulcrum,  brake-band  connec- 
tions, and  turnbuckle  are  used,  as  shown,  and  for  applying  the  brake  a 
%  X  3-in.  lever  6  ft.  long.  A  semicircular  sheet-iron  cover  is  placed 
over  the  brake  wheel  to  protect  it  from  the  weather. 


356 


DETAILS  OF  PRACTICAL  MINING 


A  %-in.  or  J^-in.  wire  tiller-rope  is  used  in  the  shaft  with  a  20-ft. 
length  of  chain  on  the  end.  In  operation  the  timber  truck  is  run  up  to 
the  collar  of  the  shaft  and  two  half-hitches  are  taken  around  the  timber 
or  lagging  with  the  chain.  One  of  the  landers  then  raises  the  load  by  turn- 
ing the  drum  with  a  cant  hook  in  the  1-in.  holes  near  one  end,  until  the 
load  slides  off  the  truck  into  the  shaft,  the  second  lander  meanwhile 
holding  the  weight  by  means  of  the  brake  lever.  The  load  is  steadied 
by  the  first  lander  and  is  then  lowered  to  the  bottom.  Steel  tram  cars, 
weighing  approximately  1J^  tons,  have  been  lowered  easily  and  slowly 
with  one  of  these  windlasses.  It  is  intended  to  arrange  a  set  of  gears, 
similar  to  an  ordinary  hand  winch,  on  the  brake-wheel  end  of  the  drum, 
so  that  a  load  can  be  raised  off  the  timber  truck  without  using  the  cant 
hook.  For  if  the  load  drops  even  a  very  short  distance,  the  lander  us- 


•-«- 

FIG.    280. IRON   WINDLASS    FOR    LOWERING    TIMBER. 

ing  the  cant  hook  is  liable  to  be  hurt.  The  first  of  these  iron  windlasses 
was  made  in  1910  in  the  shops  of  the  Oliver  Iron  Mining  Co.,  and  was 
used  in  the  Chisholm  mine.  They  have  proved  highly  satisfactory 
for  the  service  demanded.  f 

Joplin  Type  of  Horse  Whim. — Missouri  horse  whims  are  built  on 
the  idea  of  placing  the  drum  and  brakes  at  the  collar  of  the  shaft,  leav- 
ing the  control  of  the  horse  to  word  of  mouth.  This  entails  no  danger 
from  the  horse  or  mule  becoming  unmanageable,  as  the  driving  shaft 
can  easily  be  thrown  out  of  gear  with  the  drum  and  the  bucket  held  in 
the  shaft  by  the  brake  lever,  the  same  lever  being  used  for  both  opera- 
tions. The  headframe  used  with  these  hoists  is  made  high  so  that 
where  the  ground  is  flat  an  upper  floor  may  be  built,  which  is  necessary 
in  order  to  get  dumping  room.  On  that  account  the  brake  lever,  a 
piece  of  3  X  3-in.  timber,  is  made  long  enough  for  the  driver  to  control 
the  hoist  from  the  upper  floor  while  landing  the  bucket. 

The  design  of  the  whim  is  shown  in  Fig.  281.  The  horsepower  gear 
is  so  placed  that  a  14-ft.  tumbling  rod  will  connect  with  the  drum  shaft. 
The  horse  is  attached  to  a  sweep,  12  to  14  ft.  long,  and  as-  there  are 


HOISTING,  LOWERING,  TRANSPORTING 


357 


77  teeth  on  the  driving  gear  and  12  on  the  pinion,  and  as  the  drum  is  a 
little  more  than  10  in.  in  diameter,  the  bucket  is  raised  about  17  ft.  to 
one  journey  of  the  horse  around  the  ring.  A  knuckle  is  used  to  connect 
the  tumbling  rod  to  the  shaft  of  the  power  pinion  as  well  as  to  the  shaft 
of  the  hoisting  drum. 

The  drum  is  carried  on  a  4  X  4-in.  oak  frame,  as  is  also  the  driving 
gear.  The  drum  frame  is  securely  fastened  to  the  frame  of  the  derrick 
in  an  upright  position.  The  rope,  which  is  generally  a  discarded  J^- 
in.  rope  from  a  steam  hoist,  reels  directly  on  the  drum  from  the  top  sheave. 
To  prevent  the  bucket  from  running  back  when  the  drum  is  in  clutch, 
a  ratchet  and  dog  are  provided.  These  are  shown  in  the  illustration  and 
are  marked  A  and  B.  The  drum  is  loosely  mounted  on  the  drum  shaft, 
while  keyed  to  the  driving  shaft  is  a  double-arm  dog  C,  which  engages  with 


n 


'  f»™ 

[^—^5=: 

sis 

> 

3  ^ 

:i-                                ji.                 J-lf 

xUj 

5  *•  J 

1 

If 

L 

Y 

w 

Plan  of  Powe  r  Frame 


Section  X-Y 


Plan  of  Drum  Frame 


FIG.    281. DRIVE    GEAR    AND    HOISTING    DRUM    OP    JOPLIN   FRAME. 

the  two  plugs  D,  forming  part  of  the  end  casting  of  the  drum.  An  outer 
groove  is  made  in  this  casting  for  the  brake  strap  Ej  which  is  lined  with 
leather,  since  wood  is  too  bulky  for  brake  lining  on  such  a  hoist.  Pieces 
of  old  belt  are  used  for  this  purpose;  it  lasts  well,  and  gives  a  good  grip 
on  the  drum.  The  brake  lever  is  fulcrumed  either  on  the  top  cross- 
brace  of  the  drum  frame  or  else  on  a  2  X  6-in.  crosspiece  nailed  to  the 
headframe  about  18  in.  from  its  lower  end.  This  is  a  loose  fastening 
permitting  side  swing  to  the  lever,  as  it  is  by  the  side  throw  of  the  brake 
lever  that  the  drum  is  thrown  into  or  out  of  clutch  with  the  dogs  on  the 
driving  shaft. 

ROLLERS  AND  SHEAVES 

Rope  Idlers  for  Incline  Shaft  (Bull.,  American  Institute  of  Mining 
Engineers). — The  shaft  of  the  Raven  mine,  Butte,  Mont.,  is  an  incline 
1700  ft.  long  and  with  various  dips.  At  the  top  the  dip  is  70°  and  gradu- 
ally flattens  until  at  the  300-ft.  level  it  is  only  47°.  This  dip  continues 


358  DETAILS  OF  PRACTICAL  MINING 

to  the  1100-ft.  level,  below  which  it  curves  with  a  125-ft.  radius  to  78°. 
The  shaft,  furthermore,  does  not  lie  in  one  vertical  plane,  so  that  the 
hoisting  rope  not  only  rubs  at  intervals  on  both  the  hanging  and  foot- walls, 
but  presses  strongly  against  the  west  dividers  near  the  collar,  while  300 
ft.  below,  it  runs  close  to  the  east  end-plates. 

The  early  operators  used  no  idlers,  and  wall  plates  cut  6  in.  deep  by 
the  rope  resulted.  Later  operators  first  attempted  to  overcome  the 
excessive  friction,  and  the  wear  of  rope  and  wall  plates,  by  introducing 
solid  cast-iron  idlers,  3  in.  in  diameter.  To  allow  for  the  travel  of  the 
rope  from  side  to  side,  some  of  these  had  to  be  3  ft.  long  and  were  ex- 
tremely heavy.  Judging  from  the  appearance  of  the  old  idlers  of  this 
type  found  at  the  mine,  they  often  failed  to  turn  in  the  bearings,  which  is 
not  surprising  when  it  is  considered  that  they  would  have  to  make  1000 
r.p.m.  under  ordinary  hoisting  conditions. 

The  next  rolls  were  of  wood,  6  in.  in  diameter,  with  an  iron  band  about 
each  end,  and  a  pintle  of  1-in.  round  steel  driven  in  at  the  ends  to  serve 
as  a  shaft.  These  wore  rapidly,  and  were  soon  replaced  by  rolls  made 
from  water  pipe,  5  or  6  in.  in  diameter,  cut  to  the  desired  length  and 
fitted  with  a  wooden  cylinder  into  which  the  pintle  was  driven.  Where 
the  idlers  were  used  on  the  hanging  wall  of  the  shaft  the  original  bearing 
was  simply  a  piece  of  J^  X  Ij^-in.  strap  iron,  10  in.  long,  turned  up  at 
the  end  in  a  circle  of  IJ^-in.  diameter.  A  small  hole  served  for  oiling, 
and  common  black  oil  or  filtered  oil  from  engine  bearings  and  compressor 
bearings  was  used.  When  the  rolls  were  to  be  placed  on  the  foot-wall, 
the  bearings  were  made  from  two  pieces  of  1  X  3-in.  steel,  6  in.  long. 
A  half  cylinder  was  cut  from  a  side  of  each  piece  and  the  two  spaces 
together  formed  a  bearing.  Oil  holes  were  provided,  and  in  some  cases 
holes  were  bored  through  the  two  pieces  so  that  they  could  be  screwed 
or  spiked  to  the  wall  plates.  The  later  practice  was  to  forge  the  bear- 
ings from  1  X  3-in.  steel,  and  to  drill  two  holes  at  each  end  for  %-in. 
lagscrews,  by  which  the  bearings  were  fastened  to  the  timbers.  These 
bearings  were  finally  used  on  both  foot  and  hanging  wall.  Similar  idlers 
were  so  placed  as  to  protect  the  dividers  and  end  plates. 

The  difficulty  of  proper  oiling  presented  the  greatest  obstacle  to 
satisfactory  results  from  this  type  of  idler.  As  the  clearance  between  the 
skip  and  the  hanging-wall  plates  was  sometimes  less  than  an  inch,  there 
was -not  room  for  large  oil  or  grease  cups.  In  addition,  the  bearings  were 
liable  to  get  full  of  grit,  especially  when  wet  ore  was  being  hoisted. 
Grease  cups  were  generally  unsatisfactory,  although  several  kinds  of 
grease  were  tried,  and  especial  attention  was  paid  to  having  that  which 
was  suited  to  the  temperature  of  the  shaft.  In  any  event,  it  was 
necessary  that  the  rolls  be  examined  and  the  oil  cups  filled  every  two  days, 
which  meant  the  cessation  of  hoisting  for  two  hours.  The  bearings  wore 


HOISTING,  LOWERING,  TRANSPORTING 


359 


rapidly  and  the  rollers  tended  to  get  out  of  line.  The  full  skip  weighed 
over  3  tons,  and  where  the  shaft  flattened  near  the  surface,  the  pressure 
against  the  idlers  was  heavy.  It  was  only  by  distributing  this  weight 
over  idlers  placed  but  5  ft.  apart  that  anything  approaching  satis- 
factory service  could  be  obtained  at  this  point. 

To  obviate  the  necessity  for  so  much  attention,  the  idler  shown  in 
Fig.  282  was  devised.  The  roller  is  extra-heavy  6-in.  pipe,  %  in.  thick, 
20  in.  long,  in  each  end  of  which  is  pressed  a  cast-iron  head,  and  through 
which  passes  a  1  J^-in.  steel  shaft.  This  turns  in  a  self-lubricating  bearing 
carried  by  a  bracket  in  a  ball-and-socket  shell,  which  prevents  cramping. 
As  a  preliminary  to  adopting  these  bearings,  two  types  of  graphite  and 
bronze  self-lubricating  bushings  were  tried  side  by  side  in  the  incline 
for  three  months.  The  one  proving  most  satisfactory  had  cylindrical 


,:Ball  ^Socket Shelf 
\    and  Brackets 


Steel 


6X/6X/4 
Roller 


Assembly 


"Self  Lubricating 
Bushing 

Detail  of  Bearing 


PIG.    282. IMPROVED    ROLLER    AND    ITS   BEARING. 

bodies  of  graphite  Y±  in.  in  diameter  set  in  the  bronze,  or  "metal- 
line," bushing  at  about  %-in.  centers.  One  end  of  the  bearing  is  entirely 
closed,  the  end  thrust  being  taken  by  a  steel  disk,  which  also  serves  for 
forcing  out  the  bushing  when  it  is  worn.  The  other  end  of  the  bearing  is 
protected  from  grit  by  a  felt  washer.  This,  however,  also  retains  the 
fine  particles  of  metal  and  graphite,  and  in  time  this  gummy  matter 
causes  the  bearings  to  bind.  Occasional  cleaning  of  the  bushings  with 
kerosene  obviates  this  trouble.  The  cap  is  hinged  at  one  side  and 
fastened  at  the  other  with  a  hinged  bolt  so  the  roller  and  bushing  can 
be  easily  removed.  The  bearings  can  be  turned  through  90°,  and  the 
roll  turned  end  for  end,  permitting  the  advantage  of  full  wear.  The  whole 
is  carried  in  a  casting  which  is  fastened  to  the  wall  plates  with  %-in. 
lags  crews.  These  idlers  have  been  in  use  nearly  a  year  and  are  satis- 
factory. While  with  rapid  and  continuous  hoisting  the  bearings  become 
quite  hot,  they  do  not  bind  if  they  are  cleaned  occasionally. 


360 


DETAILS  OF  PRACTICAL  MINING 


For  the  lower  part  of  the  shaft,  where  the  rope  runs  true  and  the 
inclination  is  78°,  the  idlers  are  merely  common  sheave  wheels,  cast  solid 
and  keyed  on  a  shaft  of  1-in.  cold-rolled  steel.  This  has  a  total  length  of 
13  in.  These  sheaves  are  9  in.  in  diameter,  with  a  3-in.  face,  having  a 
groove  \y^  in.  deep,  1  in.  wide  at  the  bottom  The  bearings  are  maple 
blocks,  4X4X6  in.,  bored  to  receive  the  shaft,  and  provided  with  an 
oil  hole.  These  are  fastened  to  the  wall  plates  with  six  spikes. 


-J-i » - - -->J 

FIG.    283. PIPE    SECTION    FITTED    WITH    CAST   ENDS. 


The  wood-filled  pipe  idlers  with  forged  bearings  cost  at  Butte  about 
$8  each,  including  bearings.  The  idler  with  the  self-lubricating  bearings 
costs  $15,  but  the  difference  is  quickly  saved  in  decreased  cost  of  atten- 
tion. The  solid  cast  sheaves  weigh  26  Ib.  They  cost,  when  fitted 
with  a  shaft,  but  excluding  the  maple  bearings,  $2.75  each. 

Roller  of  Pipe. — A  satisfactory  horizontal  or  vertical  roller  may  be 
made  from  a  piece  of  discarded  pipe  by  fitting  the  ends  with  castings,  as 
shown  in  Fig.  283.  These  castings  may  be  kept  in  stock  for  the  several 


Section  A~B 

FIG.    284. GUIDE    ROLLER    MADE    OF    PIPE    AND    OLD    WHEELS. 

diameters  of  pipe,  and  in  case  there  is  considerable  lateral  movement 
to  the  cable  tending  to  make  it  leave  the  roller,  the  castings  should  be 
made  with  high  flanges. 

Roller  of  Pipe  and  Wheels. — Skip-  and  tram-car  wheels  discarded 
because  of  flange  or  tread  wear  may  be  utilized  for  rollers  by  driving  the 
tread  of  the  wheels  into  the  ends  of  wroughizirojnjripe  of  proper  diameter 
and  length.  The  pipe  is  then  riveted  to  the  tread  of  the  wheels,  as  shown 


HOISTING,  LOWERING,  TRANSPORTING  361 

in  Fig.  284.  This  type  of  roller  is  particularly  suited  for  rope  carriers  on 
inclined  hoistways  where  the  rope  has  some  lateral  travel,  for  knuckles 
and  for  side  rollers  to  guide  the  rope  around  horizontal  curves. 

Rope  Guide  to  Foot-wall  Sheaves  (By  Clarence  M.  Haight). — A 
simple  but  effective  method  of  guiding  a  hoisting  rope  to  its  sheaves  on  the 
foot-wall  of  an  inclined  shaft  is  shown  by  the  accompanying  drawing, 
Fig.  285,  which  explains  itself.  The  brackets  are  used  by  the  New  Jersey 
Zinc  Co.  on  its  main  shaft  at  Franklin  Furnace,  N.  J.  This  shaft  dips 
about  50°;  the  tracks  are  6J^  in.  deep,  and  are  supported  on  concrete 
piers.  The  guides  are  made  of  %-in.  round  iron,  supported  by  angles, 
as  shown.  The  sheaves  are  of  iron  with  a  wearing  surface  of  hard 
rubber. 


FIG.    285. BRACKET    FOR    GUIDING    HOISTING    ROPE    TO    SHEAVE. 

Substitute  for  Rollers  in  Incline  (By  H.  H.  Hodgkinson). — To  pull 
rock  or  ore  up  grade  in  cars  for  300  or  400  ft.,  a  small  drill-column  hoist 
was  used,  having  a  rope  speed  of  80  ft.  per  minute  with  a  pull  of  500  lb.; 
it  was  found,  however,  that  the  hoist  on  being  tested  to  the  limit  had  a 
pull  of  over  1000  lb.  at  about  half  the  speed.  Because  of  the  weight  to 
be  pulled  and  the  small  diameter  of  the  hoist  drum,  a  %-in.  galvanized 
plow-steel  rope  was  used.  So  small  a  rope  had  to  be  kept  from  dragging 
upon  the  ground  or  it  would  soon  have  worn  out.  Rollers  were  first 
tried  for  keeping  the  rope  off  the  bottom,  but  proved  unsuccessful,  inas- 
much as  the  weight  of  the  rope  was  not  enough  to  revolve  them.  Further- 
more, although  they  were  only  about  12  ft.  apart,  the  rope  dragged  on  the 
ground  between  them  when  the  car  was  lowered. 

Therefore,  as  a  substitute  for  the  rollers,  an  old  J^-in.  hoisting  rope 
was  stretched  from  the  point  where  the  cars  were  loaded  to  the  point 


362 


DETAILS  OF  PRACTICAL  MINING 


where  they  were  dumped,  firmly  anchored  at  each  end  and  tightened  by 
means  of  two  turnbuckles,  Fig.  286.  This  rope  was  8  ft.  above  the 
center  of  the  track;  on  it  double-wheel  trolleys  were  hung  at  20-ft. 
intervals;  the  upper  wheels  traveled  on  the  J^-in.  rope,  while  the  lower 
wheels  carried  the  J4-in.  hoisting  rope.  As  the  car  was  hauled  up,  these 
trolleys  all  advanced  along  the  J^-in.  rope  until  the  car  reached  the 
dumping  point.  The  trolley  wheels  were  %  X  3-in.  pulley-block  wheels 
with  ^-in.  bolts  as  shafts;  the  yoke  was  made  of  %  X  2-in.  iron.  The 
grade,  however,  was  not  great  enough  to  cause  the  trolleys  to  travel 


Iron  Rings- 


No.  10  gal v.  iron  n>ire^_ 


CAR.    READY  TO  BE  HOISTED 


CAR   BEING   HOISTED,  TROLLEYS  AND  HEMP    ROPE   CLOSING  UP 


CAR  BEING    LOWERED,  TROLLEYS   OPENING  OUT 
FIG.    286. DIAGRAMMATIC    REPRESENTATION    OP    INCLINED     HAULAGE     INSTALLATION. 

down  the  incline.  In  order  to  make  them  take  their  respective  positions 
again,  a  No.  10  galvanized  iron  wire  was  suspended  at  the  same  elevation 
and  parallel  to  the  J^-in.  rope,  but  3  ft.  to  one  side,  and  was  also  tightened. 
In  order  to  avoid  confusion,  it  is  shown  in  the  illustration  as  placed  above 
the  J^-in.  rope.  On  this  wire  were  placed  two  small  iron  rings  between 
each  pair  of  trolleys.  A  %-in.  hemp  rope  was  then  used  to  connect 
trolleys  and  rings  in  series  as  shown.  The  last  trolley,  that  nearest  the  car, 
was  connected  to  the  car  by  means  of  the  same  rope.  The  descending 
car  by  means  of  the  hemp  rope  pulled  the  trolleys  back  down  the  %-iu. 


HOISTING,  LOWERING,  TRANSPORTING  363 

rope  and  spaced  them  properly.  The  rings  on  the  small  wire  looped  up 
the  hemp  rope  and  took  up  its  slack  so  that  it  did  not  become  tangled, 
or  drag  on  the  ground. 

Sheave-wheel  Lining  (By  G.  L.  Sheldon). — The  rubber  lining  used 
to  lighten  the  wear  on  sheave  wheels  and  to  keep  wire  cable  from  slipping, 
frequently  cuts  out  when  the  wheels  are  run  at  short  angles.  The  fol- 
lowing method  of  relining  the  wheel  will  be  found  satisfactory  after  all 
of  the  old  pieces  of  rubber  have  been  removed.  Unwind  an  old  piece 
of  large-size  manila  rope  and  wind  into  the  sheave  wheel  a  single  strand 
of  the  rope,  applying  a  steady  tension.  As  each  layer  of  rope  is  run  on 
the  wheel  saturated  it  with  pine  tar.  Continue  the  operation  until  the 
lining  reaches  the  desired  thickness.  A  liberal  allowance  of  tar  should  be 
applied  to  the  last  layer  of  rope  and  the  wheel  should  be  allowed  to  stand 
from  12  to  18  hr.  before  using.  This  lining  serves  just  as  well  as  rubber 
and  is  far  cheaper.  Coal-tar  or  melted  pine-pitch  gum  may  be  used  in 
place  of  the  pine  tar. 

ROPE 

Reversing  Rope  on  Single-drum  Hoist  (By  R.  S.  Schultz,  Jr.) — It  is 
well  known  that  the  life  of  a  hoisting  rope  can  be  considerably  lengthened 
by  reversing  it  at  the  proper  time.  This  is  due  to  the  fact  that  the  weight 
of  the  rope  itself  brings  a  heavier  load  on  the  drum  end  of  the  rope  and 
causes  that  end  to  fatigue  more  rapidly.  With  a  two-drum  hoist,  re- 
versing the  ropes  is  a  simple  process,  but  with  a  single  drum,  and  espe- 
cially with  a  long  rope  of  large  diameter,  the  change  becomes  more  of 
a  problem.  By  using  two  old  cable-reels,  reversal  can  be  made  by  wind- 
ing the  rope  from  the  drum  on  to  one  of  the  reels,  rewinding  to  the  second 
reel  and  then  rewinding  on  the  drum,  but  this  is  a  slow,  tedious  operation 
and  requires  considerable  preparation. 

The  following  method  is  simple,  comparatively  rapid,  and  requires 
little  or  no  preparation  other  than  clearing  a  small  space  in  front  of  the 
engine  house.  The  skip  or  cage  is  hoisted  to  the  collar  of  the  shaft, 
securely  fastened,  and  the  rope  detached.  The  end,  just  above  the 
socket,  is  tightly  wound  with  wire  to  prevent  raveling;  the  socket  is  cut 
off  and  the  rope  wound  over  the  sheaves  on  the  drum  until  the  end  is  at 
the  cleared  place  in  front  of  the  engine  house.  The  hoist  is  then  reversed, 
and  the  rope  coiled  on  the  ground  in  a  large  figure  eight.  Then  the  coils 
are  taken  a  few  at  a  time  and  thrown  over  until  the  whole  rope  is  reversed. 
The  former  skip-end  is  then  refastened  to  the  drum,  the  rope  rewound  on 
the  drum,  the  end  pulled  over  the  sheave,  the  socket  rebabbitted  and  the 
rope  made  fast  to  the  skip  or  cage.  Special  care  must  be  taken  to  bend 
the  rope  naturally  in  coiling  and  uncoiling,  otherwise  a  serious  kink  may 
result. 


364  DETAILS  OF  PRACTICAL  MINING 

In  one  case,  using  this  method,  seven  men  reversed  3000  ft.  of  IJ-^-in. 
plow-steel  rope  in  about  four  hours,  including  rebabbitting  the  socket 
on  the  skip-end.  Considerably  better  time  could  have  been  made,  had 
speed  been  necessary. 

Reversing  Rope  with  Single  Coil  (Joseph  Hocking). — There  is  a 
better  method  than  that  of  Mr.  Schultz  for  reversing  a  rope  on  a  single- 
drum  hoist,  provided  that  the  rope  is  no  longer  than  2000  to  4000  ft., 
and  that  there  is  a  space  about  50  ft.  square  available  outside  of  the 
engine  house  or  shaft  house.  The  method  consists  of  starting  a  coil 
about  10  or  15  ft.  in  diameter  and  continuing  coiling,  working  toward 
the  outside  until  the  rope  is  all  off  the  drum;  it  is  easy  to  lay  three  coils 
to  a  foot.  With  the  rope  off  the  drum,  all  that  is  necessary  is  to  cut  the 
socket  end  from  the  rope,  fasten  the  socket  to  the  other  end,  which  will 
be  at  the  outside  of  the  coil,  fasten  the  inside  end  to  the  drum  and  wind 
it  up. 

Reversing  Rope,  Using  Power  of  the  Hoist  (By  C.  M.  Rasmussen). — 
It  is  not  necessary  to  do  by  hand  all  the  hard  and  dirty  work  of  reversing 
a  rope,  when  the  engine  can  do  it.  If  the  rope  has  to  be  rewound  on  ac- 
count of  slackness  on  drum,  or  the  wearing  parts  in  the  rope  have  to  be 
shifted,  or  the  rope  has  to  be  turned  end  for  end,  then  the  following  is 
the  best,  cleanest  and  quickest  way  a  rope  can  be  reversed,  requiring  less 
than  two  hours  for  one  from  4000  to  5000  ft.  long: 

Block  the  skip  or  cage  at  the  surface;  unfasten  the  end  of  the  rope 
and  coil  up  enough  rope  to  go  over  the  headgear  and  be  fastened  to  the 
engine  drum  later.  Then  for  a  1^-in.  diameter  rope  get  a  20-in.  single- 
sheave  wheel,  unturnable,  and  put  around  the  wheel  the  bight  of  the  slack 
rope  coiled  up.  Fasten  the  block,  unturnable,  to  the  bridle  of  the  skip. 
Fasten  the  free  end  of  the  rope  above  the  skin  with  strong  chains  or 
clamps.  Then  let  the  engine  pull  the  rope  tight,  take  the  blocking  away 
from  under  the  skip  and  let  the  skip  run  down  the  shaft  with  double  rope. 
When  all  the  rope  is  off  the  engine  drum,  fasten  this  end  of  the  rope  in 
the  headgear  also  with  chain  or  clamps.  Then  unfasten  the  former  end 
and  pull  the  one  end  down  and  the  other  up  over  the  headgear  and 
fasten  to  the  engine.  When  ready  pull  the  rope  tight,  take  the  chain 
off  the  end  of  the  rope  first  made  fast,  signal  to  the  skipman  below  to  fill 
the  skip  at  any  handy  ore  box  with  rock,  let  any  slack  rope  already  on  the 
drum  off  again  by  lowering  the  skip  and  then  pull  the  loaded  skip  to  the 
surface.  Block  the  skip  and  take  the  20-in.  sheave  wheel  off  the  skip,  and 
unchain  the  new  end  of  the  rope  and  fasten  it  to  the  skip.  Take  the  block- 
ing from  under  the  skip,  and  the  job  is  finished.  All  this  work  seems 
complicated  on  paper,  but  when  once  tried  will  be  found  easy  and  can 
be  done  in  much  less  time  than  coiling  a  mile  of  rope  on  the  ground. 
If  the  rope  requires  lubricating,  that  can  also  be  done  at  the  same  time. 


HOISTING,  LOWERING,  TRANSPORTING 


365 


Put  the  grease  box  across  the  shaft,  and  pass  the  one  rope  going  down 
through  the  hot  grease. 

Lubricating  Box  for  Horizontal  Hoisting  Rope  (By  R.  B.  Wallace). — 
An  apparatus  applicable  to  lubricating  a  hoisting  rope  which  is  hori- 
zontal or  nearly  so  in  some  portion  of  its  course,  is  illustrated  in  Fig. 


L  ubricarrf-  .--Safe^-35^ 


FIG.    287. BOX    FOR    LUBRICATING    FLAT-LYING    HOISTING    ROPE. 


287  in  longitudinal  section.  It  consists  of  a  wooden  or  metal  box  which 
has  a  removable  cover  and  is  bored  so  that  the  rope  can  pass  through. 
It  is  7}/£  X  18  X  32  in.  as  shown.  The  lubricant  is  contained  in  the 
bottom  of  the  box  and  is  picked  up  on  a  wheel  and  carried  to  the  rope, 
the  wheel  being  actuated  by  the  rope  running  over  its  top.  The  wheel 


FIG.    288. WRENCH    FOR   ROPE    WIRES. 

is  a  cast-iron  idler  sheave  running  free  on  a  2-in.  shaft  which  is  held  in 
holes  in  the  box  sides  by  cotter  pins.  There  are  two  rubber  or  leather 
washers  W,  partially  free,  which  serve  to  clean  the  rope  of  excess  oil. 

Tool  for  Bending  Rope  Wires  in  Socket  Connection  (By  Joseph 
Goldsworthy) . — The  method  of  fastening  a  hoisting  rope  into  a  conical 


366 


DETAILS  OF  PRACTICAL  MINING 


socket  is  well  known.  As  usually  practised  it  involves  bending  each  wire 
in  the  rope  end  inward  to  form  a  hook.  For  forming  the  hooks,  a  piece 
of  round  steel,  made  up  in  the  shape  of  a  T  with  a  slot  in  the  end,  as  shown 
in  Fig.  288,  will  be  found  more  convenient  to  use  than  pliers. 

Single-screw  Wire-rope  Clip  (By  A.  Livingstone  Oke). — Fig.  289 
shows  a  new  form  of  clip  for  fastening  wire  ropes  together.  It  consists 
of  a  steel  link,  made  flat  as  shown  in  the  section.  The  sides  of  this  link 
fit  in  two  grooves  or  channels  cut  in  the  inside  of  a  nut.  The  inside 
dimension  of  the  link  is  just  sufficient  to  clear  the  tops  of  the  threads 
of  a  plug  which  works  in  the  nut.  The  outer  end  of  this  plug  is  square 
so  that  it  can  be  turned  by  a  spanner.  Between  the  plug  and  the  two 
ropes  is  a  piece  of  iron  grooved  slightly  on  one  face,  to  fit  neatly  on  the 
rope  which  comes  next  to  it.  The  ends  of  the  link  have  wings  on  them. 
If  it  is  impossible'  to  pass  the  ropes  through  the  link  when  the  nut  is  on, 


PIG.    289. CROSS-SECTIONS    THROUGH    ROPES    AND    CLIP    AND    THROUGH    NUT. 

then  a  special  link  with  long  ends  instead  of  the  wings  can  be  employed, 
the  ends  to  be  hammered  back  when  in  position  on  the  ropes. 


TRANSPORTING 

Drag  Scraper  for  Handling  Dump  (By  Frederick  W.  Foote). — The 
Portland  mill,  at  Victor,  Colo.,  was  erected  to  treat  the  low-grade  dump 
material  from  the  mine.  The  dump  contained  about  2,500,000  tons 
with  an  average  value  of  about  $3  per  ton.  It  was  found  advisable 
to  take  the  supply  from  the  top  of  the  dump.  A  cheap  and  efficient  means 
was  devised  and  put  into  operation  whereby  the  material  was  elevated 
to  the  top  of  the  dump.  It  consisted  of  a  drag  scraper,  Fig.  290,  con- 
nected to  a  IJ^-in.  endless  cable  which  ran  through  a  pulley  fastened  at 
the  bottom  of  the  dump  and  around  the  hoist  drum  at  the  top.  An 
electric  hoist  of  1 12  hp.  was  used  and  the  cost  was  about  1  ct.  per  ton  of 
material  raised.  The  scraper  required  about  two  days  for  its  con- 
struction. The  body  was  of  J^-in.  boiler  plate  and  the  teeth  of  cast 


HOISTING,  LOWERING,  TRANSPORTING 


367 


iron.  The  life  of  such  a  scraper  depends  on  the  character  of  the  material 
handled  and  the  speed  of  handling.  The  one  described  handled  loose 
rock,  and,  in  almost  continuous  operation,  lasted  from  two  to  three 
weeks. 


TOOTH 


FIG.    290. CONSTRUCTION    OP    SCRAPER    AND    DETAIL    OF    TOOTH. 

Single-track  Cableway  (By  E.  Praetorius). — A  cableway  of  unusual 
design,  illustrated  in  Fig.  291,  was  installed  at  the  Rosas  mine  in  Sardinia. 
Its  novel  feature  consists  in  the  fact  that  the  two  buckets  travel  on  the 


FIG.    291. BUCKETS    AND    CARRIERS. 

same  rope,  provision  for  passing  at  the  midpoint  being  made  in  an 
ingenious  manner.  To  the  carrier  of  each  bucket  are  attached  two  arms 
extending  parallel  to  the  track  rope,  and  above  it.  These  arms  are  pivoted 


368  DETAILS  OF  PRACTICAL  MINING 

where  attached  to  the  carrier  and  the  one  on  the  ascending  side  is  kept 
elevated  above  £he  rope  by  means  of  a  flat  steel  spring  inserted  below  it. 
The  tops  of  these  arms  form  tracks  which  take  the  wheels  of  the  other 
carrier  just  as  the  rope  does.  When  the  buckets  meet,  the  carrier  wheels 
of  the  ascending  bucket  mount  the  carrier  arms  of  the  descending  bucket 
and  ride  over  them.  The  spring  in  the  upper  arm  yields  under  the  weight 
of  the  ascending  bucket,  so  as  to  permit  the  arm  to  come  down  on  the 
rope  and  deliver  the  carrier  wheels  to  the  rope  again.  The  ends  of  the 
arms  are  made  fantailed  so  as  to  guide  them  to  the  rope.  One  bucket  is 


PIG.    292. DEVICE    PERMITTING    TWO    BUCKETS    TO    PASS    ON    SINGLE    ROPE. 

suspended  from  the  carrier  by  a  much  longer  arm  than  the  other,  this 
arm  having  an  offset  portion  to  permit  the  passage  of  the  other  bucket. 

The  length  of  the  cableway  is  1115  ft.  and  it  overcomes  a  difference 
in  elevation  of  223  ft.  The  track  rope  is  %  in.  in  diameter  and  the 
haulage  rope  is  %e  m-  The  weight  of  each  bucket  and  carrier  is  220 
Ib.  and  it  carries  a  load  of  660  Ib.  The  speed  of  the  buckets  is  such  that 
the  1116  ft.  is  covered  in  65  to  70  sec. 

Single-track  Cableway  (Herbert  K.  Scott).— Fig.  292  illustrates  a 
single-track  cableway  similar  to  that  described  by  E.  Praetorius  and  no 
additional  description  is  necessary  more  than  the  noting  of  the  fact  that 
in  this  case  the  carriers  for  the  two  buckets  differ  in  design  -and  the  one 


HOISTING,  LOWERING,  TRANSPORTING 


369 


shown  on  top  always  rides  over  the  other  whether  it  is  descending  or 
ascending. 

ACCESSORIES 

Loading  Derrick  at  Shaft  Collar   (By  Clarence  M.   Haight).— At 
the  Palmer  shaft  of  the  New  Jersey  Zinc  Co.'s  mine  at  Franklin  Furnace, 

/Removable 
?uardRail 
j,      P/pes,efc. 


FIG.    293. RELATION   BETWEEN   DERRICK,    SHAFT,    TRACKS,    ETC. 


FIG.    294. SWINGING   BAR    IN    HEADFRAME    TO    STOP   BUCKET    FROM    SWINGING. 

N.  J.,  the  derrick  illustrated  in  Fig.  293  is  used  for  loading  timber,  rails 
and  other  material  on  the  shaft  cages.  As  shown,  it  can  reach  all  the 
compartments  of  the  shaft  as  well  as  cars  spotted  on  the  railroad  track. 

24 


370  DETAILS  OF  PRACTICAL  MINING 

The  mast  is  made  of  14  X  14-in.  timber  and  is  supported  by  six  guy  lines; 
the  boom  is  made  of  12  X  12-in.  timber.  When  not  in  use  the  boom  is 
supported  on  a  post.  The  power  is  furnished  by  a  two-cylinder  Lambert 
engine,  operating  on  compressed  air. 

Device  to  Stop  Whirling  Bucket. — A  simple  contrivance  to  stop  the 
whirling  of  a  bucket,  and  thereby  save  time  and  trouble,  where  hoisting  is 
being  done  without  a  crosshead,  is  shown  in  Fig.  294.  It  consists  of  two 
pieces  of  2  X  4-in.  lumber  pivoted  on  the  backstay  of  the  headframe  by 
pins  and  joined  together,  in  front  of  the  headframe,  by  a  third  2  X  4-in. 
piece.  The  stop  thus  is  free  to  swing  upward,  and  is  prevented  from 
falling  by  two  supports  on  the  headframe  posts.  The  outer  face  of  the 
crosspiece  is  almost  flush  with  the  hoisting  cable,  and  the  piece  is  level 
with  the  top  of  the  bucket  when  it  is  at  an  elevation  convenient  for 
dumping. 

When  hoisting,  the  bail  of  the  bucket  may  strike  the  stop  and  lift  it 
temporarily,  but  when  the  bucket  makes  a  quarter  turn  the  stop  will  fall 
alongside  the  bail  and  prevent  any  further  whirling. 


IX 
SHAFT  CONVEYANCES 

Cages — Skips — Chairs  and  Dogs — Skip  Dumps — Transfers — Buckets- 
Bucket  Dumps 

CAGES 

Drop-bottom  Cage. — In  Fig.  295  are  shown  the  details  of  the  drop- 
bottom  cage  used  at  the  mines  of  the  St.  Louis  Smelting  &  Refining  Co., 
in  southeastern  Missouri.  The  notable  feature  of  the  cage  is  that 
the  car  is  locked  in  position  on  the  deck  by  dropping  the  central  part  of  the 
deck  track.  In  landing,  this  track  is  raised  up  level  with  the  outer  rails 
before  the  cross-braces  of  the  deck  of  the  cage  come  into  contact  with 
the  landing  chairs.  The  outer  fixed  rails  are  given  a  slight  slant  toward 
the  center  of  the  cage  so  that,  if  the  car  has  riot  been  put  on  properly, 
the  jar  of  lifting  the  cage  off  the  chairs  will  cause  it  to  run  to  the  center 
and  drop  down  into  the  recess.  Only  its  weight  holds  this  movable  por- 
tion of  the  deck  in  place  and  in  case  of  repairs  it  can  be  easily  lifted  out. 
Pans  marked  P  are  riveted  to  the  bottom  of  the  deck  so  as  to  come  up 
alongside  the  rails  and  keep  anyone  from  getting  his  toe  under  the  rails 
of  the  drop  portion.  In  this  way  possibility  of  injury  from  that  source 
during  the  hoisting  of  a  deck  load  of  men  is  prevented.  The  possibility 
of  a  car  getting  loose  in  the  shaft  and  causing  a  wreck  is  almost  completely 
eliminated  with  this  device.  A  disadvantage  is  that  the  use  of  chairs  in 
the  shaft  is  entailed. 

The  cage  is  equipped  with  the  ordinary  type  of  cam  safety  catches 
operated  by  coil  springs  and  chains  from  a  collar  on  the  drawbar.  The 
side  plate  is  punched  to  receive  the  cam  shafts  and  extends  down  the 
side  of  the  cage  to  carry  the  angle-iron  guide  shoes  S.  These  shoe  angles 
extend  clear  down  under  the  deck  of  the  cage  so  as  to  tie  the  deck  securely 
to  the  sides.  To  the  bottom,  where  the  angles  are  bent  around,  rein- 
forcing plates  G  are  riveted.  The  deck  of  the  cage  is  made  up  of  the  outer 
angle  cross-braces  M,  the  inner  braces  N,  and  the  shoe  angles  S.  The 
drop  bottom  is  made  up  of  the  cross-braces  K  and  L,  the  angle  irons  /, 
the  longitudinal  angles  H  bolted  together  back  to  back  and  the  rails  Ri. 
In  landing  the  chair  shoes  catch  the  cross-braces  L  and  raise  the  drop 
bottom  even  with  the  rest  of  the  deck. 

Cage  with  Munzner  Safety  Catches. — Cages  fitted  with  the  Munzner 
type  of  safety  catch  have  been  in  use  for  15  years  in  the  shafts  of  the  Doe 

371 


372 


DETAILS  OF  PRACTICAL  MINING 


• 

!P 


R 


r 


R 


IL  TK 

r Jl7 


*-r^  ^J      .     •* — *• 

Chain  Pul ley forSafet/Gear 


FIG.    295. ST.    LOUIS    SMELTING    &   REFINING    DROP-BOTTOM    CAGE. 


SHAFT  CONVEYANCES  373 

Run  Lead  Co.,  of  southeastern  Missouri.  This  safety  catch  was  de- 
signed by  F.  A.  Munzner,  in  Germany,  about  1893,  and  is  largely  used  in 
Saxony.  Its  action  consists  of  thrusting  pointed  knife  edges  into  the 
guides  by  a  toggle  action.  The  shape  of  the  dogs  used  in  the  Doe  Run 
mines  was  worked  out  by  Karl  Kley,  in  Saxony,  and  was  adopted,  as 
being  the  most  satisfactory,  by  O.  M.  Bilharz,  general  manager  of  the  Doe 
Run  company.  The  dogs  offer  the  advantage  as  against  the  ordinary 
type  of  toothed-cam  safety  dog,  of  stopping  the  cage  with  a  slower, 
braking  action  instead  of  with  a  sudden  grip  and  they  more  perfectly 
fulfill  the  requirements  of  a  good  safety  catch,  namely,  that  it  be  positive 
and  reliable,  quick  to  come  into  action,  but  slow  to  complete  its  action, 
and  capable  of  acting  on  guides  of  varying  thickness.  It  is  urged  against 
the  cam  dog  that  it  acts  so  quickly  as  to  tend  to  injure  the  men  riding  on 
the  cage  and  to  tear  out  the  guides.  It  also  is  likely  to  fill  with  wood  and 
possibly  thus  become  inoperative.  The  use  of  the  double  knife  edge 
minimizes  the  danger  of  splitting  the  guides  and  while  it  cuts  and  dam- 
ages them  somewhat  more  than  a  single  blade,  this  is  a  point  of  minor 
importance. 

On  one  occasion  at  the  Johannes  shaft  in  Freiberg,  the  Munzner 
attachment  stopped  a  cage  so  gradually  after  the  cable  broke,  that  the 
men  riding  did  not  realize  that  it  had  not  been  stopped  by  the  engineer. 
In  demonstrating  the  reliability  of  the  device  to  the  Doe  Run  miners, 
when  it  was  first  proposed  to  install  it,  Mr.  Bilharz  and  his  master  me- 
chanic mounted  the  cage  40  ft.  from  the  ground  in  an  experimental  tower, 
cut  themselves  loose  and  were  stopped  immediately.  In  the  15  years' 
use  of  the  Munzner  catch  in  the  Doe  Run -mines,  the  only  instance  in 
which  it  failed  to  work  was  on  one  occasion  when  the  rope  broke  with  the 
cage  20  ft.  from  the  shaft  bottom  and  the  catches  were  unable  to  take  care 
of  the  extra  weight  of  cable  and  stop  the  cage  in  that  distance.  Usually 
the  cage  stops  in  3  or  4  ft.  In  a  German  test,  a  cage  weighing  3440  Ib. 
was  allowed  to  fall  about  1.5  ft.,  when  the  safety  dogs  came  into  action 
and  sank  1%  in.  into  the  guides,  stopping  the  cage  after  a  groove  about  a 
foot  long  had  been  cut. 

On  the  Doe  Run  cages,  the  spring  is  placed  above  the  actuating  frame 
instead  of  below,  an  improvement  on  the  original  design.  The  details 
of  the  device  are  shown  in  Fig.  296.  The  dogs  D  are  carried  loose  on  the 
ends  of  the  shafts  B.  The  shafts  are  pinned  to  the  crosshead  A  and 
cross-braces  C,  making  a  rigid  frame,  which  moves  with  the  drawbar  F 
to  which  A  is  keyed.  The  dogs  are  held  on  the  shafts  by  collars  and  rest 
on  and  move  over  the  plates  E.  The  spring  V  is  held  under  the  strap  H. 
When  the  pull  comes  on  the  drawbar,  it  moves  up,  and  the  collar  7, 
keyed  to  it,  compresses  the  spring  V  until  A  strikes  the  plate  P  fastened 
to  the  cage  frame  and  thus  gives  a  positive  stop  to  upward  motion  of 


374 


DETAILS  OF  PRACTICAL  MINING 


the  drawbar  and  the  frame.  This  motion  tends  to  pull  the  points  of  the 
knives  D  away  from  the  guides.  If  the  rope  breaks  or  the  tension  is 
otherwise  released,  the  frame  is  thrust  down,  relative  to  the  cage,  by  the 
spring  V  and  the  dogs  revolving  on  B  and  lying  on  E  are  forced  with  a 
toggle  motion  to  engage  the  guides.  It  is  necessary  to  keep  the  knives 
always  sharp. 


PLAN  OF  SAFETY-DOG  FR/^ME 
B. 


•      ^ 
FRONT  ELEVATION 


SIDE  ELEVATION 


(H)    SPRING  FRAME 


(H)    SPRING  FRA 
FIG.    296. THE    MUNZNER    SAFETY   DEVICE    AS    APPLIED    TO    DOE    RUN    CAGES. 


The  bottom  of  the  drawbar  is  protected  by  a  cylindrical  hood  J  to 
prevent  pinching  the  hands  of  the  men  riding.  The  motion  of  the  frame 
and  the  dogs  is  controlled  by  the  vertical  guides  G.  The  original  design 
had  stops  to  limit  the  inward  motion  of  the  dogs.  These  are  here 
omitted.  The  guides  in  this  case  are  4  X  6  in.  The  spring  is  a  volute, 
9  X  9J^  X  2  X  H  in.,  made  by  the  A.  French  Spring  Co.,  of  Pittsburgh, 
and  has  proved  satisfactory.  The  spring  should  not  take  the  whole  load 


SHAFT  CONVEYANCES 


375 


of  the  cage  before  the  frame  catches  P,  or  the  device  will  be  too  sensitive. 
A  sharp  fluctuation  in  speed  might  tend  to  make  the  dogs  catch  and  the 
jumping  of  the  cage  after  stopping  would  bring  them  into  action.  Prob- 
ably the  adjustment  should  be  such  that  the  spring  will  take  about  80 
per  cent,  of  the  weight  of  the  empty  cage  before  the  positive  pull  comes 


..iiiil 


r                   v 

K//^/-/7  /c?  ^/Ve  £^ 
-  Clearance  on  eat. 
Side 

Platform 

:/?> 

*f         I" 

•gX-Z/ron' 
1    ^W 

JL  j^       mr    or  "V7  ,,,,/T; 

J 

^^•-rtangers-^ 


Shoe 


.{dolt 


f  Hand  Bar 


^V/ro/7-''' 


"Center  Bolt 


/*S    a  a        a  a  ^f\ 

/X~  ,">,     t  x\ 

>^      ^llron-'       V 
^o-H-om 


FIG.    297. SKELETON    CAGE,    24    FT.    HIGH. 

on  the  frame.     The  best  springs  will  deteriorate  and  should  be  frequently 
tested  to  determine  their  strength  quantitatively. 

The  weight  of  the  cage  illustrated  is  2400  Ib.  and  it  cost,  as  shown, 
about  $425,  erected  in  the  company's  shops.  One  difficulty  with  the 
design  is  the  obstruction  of  the  top  of  the  cage,  which  interferes  with 
loading  timbers,  pipe  and  rails.  The  knife-edge  principle,  however, 
should  be  applicable  to  a  cam  dog  with  satisfactory  results;  possibly  in 


376 


DETAILS  OF  PRACTICAL  MINING 


such  case,  the  edges  should  be  toothed  slightly  at  the  points  where  they 
begin  to  grip. 

Four-deck  Shaft-repair  Cage  (By  Albert  B.  Pedersen) .— Fig.  297 
shows  a  24-ft.  cage  with  four  decks  used  by  the  Chief  Consolidated 
Mining  Co.  at  Eureka,  Utah,  for  changing  guides  from  3J^  X  3J^  in. 
to  3^2  X  7  in.  After  this  work  was  done  shoes  were  put  on  the  bottom 
and  the  cage  was  used  for  regular  shaft  inspection  and  repair  work.  The 
long  cage  was  swung  from  the  bottom  of  the  ordinary  cage  by  means  of 
the  hangers  at  the  top.  The  cage  corners  were  made  of  2  X  /4-in.  strap 
iron;  2  X  M~m-  angles  attached  to  the  corner  irons  supported  wooden 
platforms;  to  the  bottoms  of  these  were  bolted  hand  bars  of  %-in.  round 


PIG.    298. CAGE    FOR    HOISTING    INJURED    MINERS    THROUGH    TIMBER    SHAFT. 

iron.  The  bottom  was  made  tapered  as  shown.  Using  this  cage  with 
one  man  on  each  deck,  about  200  ft.  of  guides  was  changed  on  an  average 
in  eight  hours. 

Ambulance  Cage  (By  L.  D.  Davenport). — If  a  miner  working  on  one 
of  the  sublevels  in  the  Chisholm  district  of  the  Mesabi  range  is  injured, 
it  is  usually  easier  to  hoist  him  up  one  of  the  timber  shafts  than  to  take 
him  to  the  bottom  level  and  hoist  him  up  in  the  skip.  At  one  time  it  was 
customary  to  use  the  powder  cage  for  this  purpose  but  this  was  so  small 
and  inconvenient  that  a  special  type  of  apparatus  was  designed.  The 
cage  shown  in  Fig.  298  is  of  sufficient  height  so  that  an  injured  man  can 
stand  or  be  supported  in  an  upright  position  if  desired.  The  large  door 


SHAFT  CONVEYANCES 


377 


in  the  front,  which  is  reinforced  with  oak  cleats,  can  be  swung  down  to 
the  ground,  making  it  easy  to  place  an  injured  man  in  the  cage.  There 
is  a  seat  on  one  side  and  the  cage  is  made  large  enough  to  accommodate 
two  men  in  case  it  is  necessary  to  have  the  injured  man  accompanied 
by  someone.  The  cage  is  light  and  strong  and  was  designed  and  built 
under  the  direction  of  the  master  carpenter  at  the  Monroe  mine. 

Latch  for  Holding  Car  on  Cage. — Fig.  299  shows  a  device  for  holding 
timber  or  other  trucks  on  the  cage,  employed  at  the  Kennedy  mine  on 
the  North  Cuyuna  range.  It  consists  of  a  horizontal  bar  of  round  iron 
held  loosely  by  staples  to  the  wooden  floor  of  the  cage,  so  as  to  revolve 
freely  but  not  to  slide.  Near  one  end  a  IJ/^-in.  round  bar  is  welded  on 
to  project  at  right  angles  and  its  end  is  split  to  form  a  fork  5  in.  across  the 


V  fc--/  Round 


PIG.    299. AN   EFFICIENT    CAR    LATCH. 

top.  The  other  end  of  the  horizontal  bar  is  made  eccentric  for  a  few 
inches  and  then  turned  at  right  angles.  The  latch  is  placed  so  that  the 
fork  will  be  at  about  the  center  of  the  cage  and  the  planes  of  the  fork  and 
of  the  bent  end  are  so  related  that  the  operator  can  slip  his  foot  under  the 
latter  when  the  fork  is  thrown  back  out  of  the  way.  The  construction 
and  dimensions  are  shown  in  1,  Fig.  299,  which,  however,  does  not  repre- 
sent the  latch  in  a  normal  position.  In  2  the  latch  is  shown  engaging  the 
wheels  of  a  truck.  The  truck  is  run  on  the  cage  until  the  space  between 
the  wheels  is  about  opposite  the  fork,  when  the  operator  throws  the 
latch  over  and  the  fork  falls  on  the  treads  of  the  wheels  and  against  the 
flanges,  at  a  point  somewhat  above  their  centers.  The  truck  is  thus  held 
against  movement  in  either  direction.  The  device  is  in  use  on  a  slow- 
moving  cage  in  a  shallow  mine.  It  would  seem  that  on  a  fast-moving 


378 


DETAILS  OF  PRACTICAL  MINING 


cage,  one,  for  instance,  actuated  by  a  first-motion  hoist,  there  would  be 
danger  that  the  fork  might  bound  out  as  the  result  of  a  jolt  and  thus  re- 
lease the  truck. 

Releasing  Hook  for  Cage  Testing. — Usually,  when  testing  the  safety 
catches  on  skips  or  cages,  the  hoisting  cable  is  attached  to  the  cage  by  a 
hemp  rope  which  is  cut  when  the  cage  is  in  the  desired  position.  The 
inspection  department  of  the  Cleveland-Cliffs  Iron  Co.,  in  the  Lake 
Superior  region,  tests  all  safety  dogs  once  each  month.  A  releasing  hook 
is  used  instead  of  the  hemp  rope  and  has  proved  more  satisfactory.  Fig. 
300  shows  the  details  of  the  hook,  which  is  strong  enough  for  a  5-ton  skip 


FIG.    300. CLEVELAND-CLIFFS    RELEASING    HOOK. 

of  the  Kimberley  type.  The  trigger  E  is  pinned  to  the  arm  D  and  operates 
in  the  slot  F  cut  in  the  arm  C.  The  trigger  catches  on  the  lower  back  edge 
of  this  slot.  The  pin  B  of  the  clevis  A,  which  fastens  the  cage  to  the 
shackle  of  the  hoisting  cable,  is  removed  and  the  clevis  attached  to  the 
releasing  hook.  The  hook  is  now  linked  into  the  drawbar  of  the  skip 
or  cage  whose  safety  dogs  are  to  be  tested.  When  the  cage  has  reached 
the  proper  position,  the  rope  attached  to  the  trigger  is  pulled,  allowing 
the  arms  D  and  C  to  separate  and  the  cage  to  fall.  At  the  Cliff  shaft  of 
the  Cleveland-Cliffs  company,  the  safety-dog  testing  is  done  at  the 
bottom  of  the  shaft  where  actual  working  conditions  as  to  slippery  guides 


SHAFT  CONVEYANCES  379 

are  more  nearly  duplicated  than  at  the  surface.  This  practice  is  open 
to  objection,  however,  if  the  bottom  guides  are  not  worn  so  much  as  those 
higher  up.  The  danger  due  to  the  dogs  cutting  up  the  guides  is  better 
tolerated  at  the  bottom  of  the  shaft  than  at  the  surface.  Should  the 
dogs  of  a  heavy  skip  refuse  to  work  and  allow  it  to  fall  on  the  stage  at 
the  collar  of  the  shaft,  damage  might  be  done  to  the  shaft  timbers;  this 
danger  is  obviated  by  the  use  of  the  bottom  of  the  shaft  for  testing 
purposes. 

Combination  Cage  and  Skip. — Fig.  301  shows  the  details  of  the  cage 
and  skip  used  at  the  No.  1  shaft  of  the  Federal  Lead  Co.,  in  southeastern 
Missouri.  There  is  a  top  deck  which  can  accommodate  a  car  and  on 
which  men  can  be  handled,  and  under  it  swung  from  the  same  frame  is 
a  lower  deck  which  carries  the  self-dumping  skip.  This  skip  holds  5.4 
tons  of  ore. 

There  are  several  interesting  features  in  the  design.  To  the  channels 
that  form  the  main  members  of  the  cage  and  skip  frames,  four  shoe 
channels  are  riveted,  two  on  the  frame  that  carries  the  skip,  and  two  on 
the  frame  that  carries  the  deck  for  the  men  and  car.  The  two  frames 
are  bolted  together  by  means  of  a  splice  plate.  The  main  channels  are 
bent  over  at  the  top  and  spliced  together  by  a  strap  A2,  through  which 
passes  the  drawbar  Al.  Under  the  two  runner  channels  and  bolted  to 
them  is  the  drawhead  casting  Bl.  This  is  contracted  at  the  center  so 
as  to  be  straddled  by  the  clevis-shaped  drawbar  Al,  which  also  straddles 
the  shock  spring  and  shock-spring  base  B2.  The  spring,  of  course,  foots 
against  the  drawhead  casting.  This  whole  mechanism  is  inclosed  by 
cover  plates  fastened  to  the  channels.  One  plate  is  riveted  while  the 
other  is  fastened  by  bolts  so  that  it  can  be  easily  removed.  On  tire 
draw  pin  ^4.3  is  a  sleeve  over  which  fits  the  clevis  by  which  the  cage-and- 
skip  frame  is  fastened  to  the  rope  shackle. 

The  chains  leading  down  to  the  safety-dog  levers  fasten  to  eye-bolts, 
through  which  the  pin  A3  passes.  The  safety  dogs,  which  are  toothed 
castings,  are  held  together  by  the  spring  S;  this  connects  with  the  two 
lever  arms  B,  which  in  turn  are  keyed  to  the  dog  shaft.  The  safety  dogs 
are  held  away  from  the  guides  by  the  pull  on  the  drawbar,  which  is 
transmitted  to  them  by  the  chains  connecting  with  the  levers  A,  which 
are  also  keyed  to  the  dog  shafts.  The  rest  of  the  cage  follows  the  ordi- 
nary lines  of  construction. 

On  the  lower  platform  of  the  cage,  it  will  be  noticed  that  there  are 
two  pivot  shafts  for  fastening  the  skip  body  to  the  frame.  This  is  to 
allow  the  skip  to  dump  in  either  direction.  Formerly  it  discharged 
into  a  pocket  on  the  opposite  side  of  the  shaft  from  that  now  in  use. 
A  peculiarity  of  the  skip  is  the  use  of  the  horns  H  to  right  it  after  dump- 
ing. The  tripping  is  accomplished  by  the  skip  rollers  following  out  on  a 


380  DETAILS  OF  PRACTICAL  MINING 


-     . .,,       -3fi/ 


DRAWBAR  A-J 


SHAFT  A-5 


FIG.  301. CAGE  AND  SKIP  AT  NO.  1  SHAFT  OF  FEDERAL  LEAD  CO. 


SHAFT  CONVEYANCES 


381 


double  runway,  as  can  be  seen  in  the  drawing  of  the  dump,  the  upper 
runway,  however,  having  only  the  bottom  track.  On  coming  down 
after  dumping,  the  skip  rollers  run  forward,  following  the  guide  runners 
until  at  the  point  of  the  dump  tracks,  the  horns  engage  with  the  nose 
rollers  of  the  dump,  and  the  body  of  the  skip  is  given  a  push  upward, 
bringing  it  back  into  an  upright  position  on  the  skip  frame.  The  other 
features  of  the  skip  do  not  need  mentioning,  as  they  follow  the  ordinary 
lines. 

SKIPS 

Light  Skip  for  65°  Incline. — Fig.  302  represents  a  %-ton  skip  designed 
for  a  Mexican  mine.     The  rounded  bottom  is  more  common  on  vertical 


O  :  O      O      CO      O      O      O      O      O      (5\  O  l^  O      O      O      O      O     Qs,  I 

~r~r,r~~~.'' ~ ~/ .  ;  ,-.->/ » -> /. « ^-s.  J\i 


FIG.    302. SMALL    CAPACITY   INCLINED    SKIP. 

than  inclined  skips.  The  extremely  small  cross-section,  1  ft.  10  in.  by 
1  ft.  11%  in.,  is  noteworthy.  The  gage  of  track  is  2  ft.,  the  wheels  are 
keyed  to  the  2-in.  axles  which  revolve  in  hardwood  boxes. 

Rear-dumping  Skip-car  (By  L.  O.  Kellogg). — At  the  Sterling  iron 
mine,  in  Orange  County,  N.  Y.,  the  flat-dipping  shaft  and  the  limited 
room  between  the  collar  and  the  hoist  make  the  employment  of  a  special 
type  of  skip  necessary.  This  is  shown  in  Fig.  303.  It  is  really  a  car  with 
an  automatic  door  on  the  bottom  end.  The  door  is  shown  closed; 
opening  is  effected  by  tripping,  two  small  wheels  coming  into  contact 
with  a  railing  erected  beside  the  track  at  the  dumping  point.  The  smaller 
wheel  first  comes  into  contact  and  unlocks  the  toggle  joint.  Then  the 


382 


DETAILS  OF  PRACTICAL  MINING 


larger  wheel  forces  the  lower  half  of  the  door  to  slide  up  outside  the 
fixed  upper  half.  As  the  car  descends  again,  the  door  is  allowed  to  drop 
and  is  locked  with  the  toggle  mechanism.  There  is  a  double  track  with 
a  tripping  railing  on  each  side  and  the  tripping  device  on  the  cars  is  put 
on  both  sides,  so  that  the  cars  can  be  used  on  either  track.  The  car 
body  is  built  with  its  bottom  higher  toward  the  upper  end.  By  this 
means  sufficient  slope  is  given  to  the  bottom  to  discharge  all  the  contents. 


FIG.    303. SKIP    CAR    FOR   INCLINE,    WITH    REAR   DISCHARGE. 


The  car,  as  used,  hoists  4  tons  of  magnetite.  It  was  built  by  the  Kil- 
bourne  &  Jacobs  Manufacturing  Co.,  of  Columbus,  Ohio,  to  fit  the 
peculiar  conditions  existing,  and  is  a  unique  type. 

Skip-bail  Lock  and  Release  (By  S.  S.  Jones). — The  device  illustrated 
in  Figs.  304  and  305  is  one  designed  to  prevent  overturning  of  the  skip 
in  the  shaft.  It  was  developed  by  W.  H.  Flannigan,  foreman  of  the  Tom 
Reed  mine  in  Arizona.  Two  notched  bars  or  latches,  A,  are  normally 
caught  over  a  square  lug  on  each  side  of  the  bail  and  are  rigidly  con- 
nected to  a  square  shaft  B  under  the  skip,  turned  for  two  bearings.  A 
lug  C  projects  from  the  middle  of  this  shaft  and  a  trigger  D  forked  at  the 
top  is  pinned  to  this.  This  trigger  is  of  the  shape  shown.  When  the 
skip  arrives  at  a  point  near  the  dump,  the  trigger  is  -caught  by  a  2-in. 
plank  covered  with  sheet  iron  and  spiked  between  the  rails.  This  forces 
the  trigger  to  revolve  until  the  upper  part  presses  on  the  shaft,  when  it 
becomes  in  effect  rigidly  connected  with  it  and  the  shaft  is  revolved  suf- 
ficiently to  release  the  latches  A  from  the  bail  lugs.  The  trigger  remains 
in  contact  with  the  plank  after  the  skip  starts  on  its  dump.  On  the 
return,  it  again  comes  into  contact  with  the  plank,  but  is  free  to  re- 
volve in  the  opposite  direction.  The  latches  are  thus  allowed  to  fall  by 
gravity  on  the  lugs.  They  are  tapered  at  the  top  so  that  the  bail  can 


SHAFT  CONVEYANCES 


383 


slip  into  place.  This  return  of  the  latches  might  be  made  more  positive 
by  the  use  of  a  spring,  but,  as  a  matter  of  fact,  this  has  not  been  found 
necessary.  The  mine  shaft  in  which  this  is  installed  has  a  dip  of  73°. 
The  dimensions  of  the  ^-ton  skip  and  the  parts  of  the  device  are  not 


Plank  between  fnzck 


PIG.   304. BAIL    LOCK    APPLIED    TO    SKIP. 


A  v  D' 

FIG.    305. DETAILS    OF    SKIP-BAIL    LOCK. 


given,  inasmuch  as  these  would  vary  with  every  installation.  The  re- 
volving shaft  is  made  of  1^-in.  square  shafting;  the  latches  and  the 
trigger  of  %  X  2-in.  bar  iron. 

Bailer  for  Winze  (By  S.  A.  Worcester). — The  800-gal.  bailing  tank 


384 


DETAILS  OF  PRACTICAL  MINING 


shown  in  Fig.  306  was  designed  for  use  in  a  winze  of  the  Camp  Bird 
mine.  It  is  arranged  to  discharge  into  a  tank  placed  at  the  south  side 
of  the  winze  in  such  a  manner  that  two  streams  flow  from  the  bottom, 
one  on  each  side  of  the  guide.  The  curved  arm  A  projecting  beyond  the 
upper  corner  of  the  bailer  is  engaged  by  a  stationary  lug  fixed  at  the 
discharge  point  in  the  winze.  This  lug  forces  the  arm  A  inward,  rotating 
the  2-in.  shaft  B  and  through  the  link  C  raises  the  rod  D  which  lifts  the 
discharge  valve,  thus  emptying  the  bailer.  The  removable  guide  shoes 
are  bolted  to  the  sides  of  the  bailer  and  are  fitted  with  liners  which  can 


Deta  i  I  of  Va  1  ve  a  nd  Seat 

(Enlarged)  Sjde  Elevat{ons 

PIG.    306. BAILING    TANK    USED    IN    CAMP   BIRD    MINE. 


readily  be  changed  in  case  of  there  being  variations  in  the  distance  be- 
tween guides.  The  sides  of  the  bailer  are  made  of  light  sheets  well 
stiffened  by  ties  and  angles  to  prevent  bulging.  The  bottom  plate,  %Q 
in.  thick,  is  stiffened  by  the  angles  that  hold  the  discharge  spout,  by  the 
valve-seat  ring,  and  by  the  two  rods  from  the  sides. 

Self -discharging,  Inclined,  Bailing  Tank  (By  M.  G.  Sohnlem). — At 
the  Maestro  shaft  of  the  mine  Socavon  de  la  Virgen  in  Oruro,  Bolivia,  the 
water  is  bailed  with  tanks  of  400  gal.  capacity.  The  water  contains  a 
considerable  amount  of  acid  and  sulphates,  so  that  the  tanks  have  to  be 
constructed  of  wood.  The  vertical  depth  of  the  shaft  is  about  600  ft. 
and  the  flow  of  water  amounts  to  5500  gal.  per  hour.  Along  the  sides 
of  the  shaft  some  clean  water  flows  in,  which  is  caught  in  a  stationary 


SHAFT  CONVEYANCES 


385 


tank  about  100  ft.  above  the  600-ft.  level,  whence  it  is  hoisted  to  the  sur- 
face. There  it  is  discharged  into  another  tank,  from  which  it  goes 
directly  to  the  feed  pumps  of  the  boilers.  The  automatic  discharge  had 
to  be  designed  in  such  a  way  that  the  acid  water  would  flow  into  a  launder 
at  the  shaft  collar,  and  the  clean  water  would  discharge  into  the  storage 
tank  about  15  ft.  higher.  The  same  bailers  are  used  for  either  acid  and 
clean  water  and  at  the  beginning  of  the  shift  a  few  buckets  of  fresh  water 
are  first  hoisted. 

The  arrangement  can  be  readily  understood  from  Fig.  307.     A  is 
the  valve  hinged  at  H.     As  soon  as  the  roller  R  strikes  the  plank  P, 


FIG.    307. BAILER    WITH    TWO    DISCHARGE    POINTS. 


which  is  placed  a  little  more  inclined  than  the  shaft,  the  lever  L  is  lifted 
and  the  valve  is  opened  by  the  connecting  rod  C.  At  the  point  M  the 
valve  has  reached  its  largest  opening.  The  upper  part  of  the  plank, 
which  is  connected  with  the  lower  part  by  angle  irons,  is  placed  at  the 
same  inclination  as  the  shaft.  If  the  tank  should  be  lifted  a  little  higher, 
as  frequently  occurs,  the  roller  travels  on  this  part  of  the  plank,  keeping 
the  lever  in  the  same  position  as  it  has  at  M,  and  consequently  the 
valve  stays  wide  open  until  the  roller  leaves  the  plank,  when  the  lever 

25 


386 


DETAILS  OF  PRACTICAL  MINING 


falls  back,  shutting  the  valve.  By  placing  another  plank  higher  up, 
the  discharge  of  clean  water  is  led  into  the  clean-water  tank.  When 
hoisting  fresh  water  the  engineer  passes  the  first  plank  quickly  so  that  the 
valve  opens  for  only  a  very  short  time  and  but  a  small  quantity  of  the 
water  is  lost. 

When  lowering  again  the  roller  has  to  pass  the  first  plank.    Therefore 
the  fork  at  the  upper  end  of  the  rod  C  is  slotted  for  some  distance  and  the" 


Plan  of  Chairs 


!< 


Opera  ting  L  ever 
Fixed  Bearing  L  andin    Floor 


FIG.    308. ONE    SET   OF   SLIDING    CHAIRS   SERVING   TWO    COMPARTMENTS. 

bolt  which  connects  the  rod  and  the  lever  can  slide  through  this  fork  until 
the  roller  comes  into  such  a  position  that  it  freely  passes  the  plank,  as 
shown.  After  leaving  the  plank  the  lever  is  brought  back  into  its  proper 
position  by  the  counterpoise  E.  Even  if  the  engineer  should  hoist  the 
tank  so  high  that  the  roller  leaves  the  plank  entirely,  he  can  lower  again 
and  then  hoist  it  to  its  proper  position.  Further  construction  details 
can  be  easily  understood  from  the  illustration.  The  planks  are  fixed 
to  the  timbers  of  the  headframe  with  crosspieces  T. 

CHAIRS  AND  DOGS 

Double  Landing  Chairs. — In  Fig.  308  are  shown  the  general  features 
of  the  design  of  the  landing  chairs  used  at  the  shaft  of  the  Desloge  Con- 
solidated Lead  Co.  in  southeastern  Missouri.  The  chair,  which  is  simple, 


SHAFT  CONVEYANCES 


387 


is  of  the  sliding  and  not  of  the  leg  type.  It  is  made  to  serve  both  com- 
partments of  the  shaft.  The  landing  bars  are  60-lb.  rails  placed  head  up. 
These  slide  upon  blocks  carried  by  the  beams  of  the  headframe.  From 
the  first  beam  the  motion  is  transmitted  by  means  of  connecting  rods 
and  double-arm  levers  to  the  landing  beam  on  the  other  side  of  the  shaft, 
which  in  this  way  is  thrown  in  at  the  same  time.  The  operating  lever  is 
attached  to  the  middle  of  the  lever  shaft  so  that  it  will  be  handy  when 
landing  either  cage.  Little  handling  of  the  two  cages  at  the  same  time 
is  necessary  at  the  collar  of  a  shaft,  so  there  does  not  seem  to  be  any 
special  reason  for  not  using  a  double  chair  at  the  surface.  Of  course, 


LimofHoistinq 
Tomr  y 


FIG.    309. DETAILS    OF    CHAIRS    FOR    DROP-BOTTOM    CAGES. 

a  double  chair  could  not  be  used  at  intermediate  shaft  stations  so  safely; 
as  it  is  often  necessary  to  lower  a  cage  past  the  one  that  is  landed  in  the 
shaft. 

Chairs  for  Drop-bottom  Cages. — The  details  of  construction  of  the 
chairs  for  the  drop-bottom  cages  used  at  the  shafts  of  the  St.  Louis 
Smelting  &  Refining  Co.,  in  southeastern  Missouri,  are  shown  in  Fig.  309. 
The  chairs  are  made  to  come  out  and  catch  the  cage  under  the  center  of 
each  side  so  as  to  lift  the  drop  part  of  the  cage  deck,  on  which  the  car  is 
resting,  level  with  the  outer  rails  of  the  deck  before  the  weight  of  the 
whole  cage  comes  on  the  chair.  The  bearings  B  and  C  are  carried  from 
a  member  of  the  headframe  to  which  they  are  securely  bolted.  In  these 
bearings  are  carried  the  chair  shafts  S  to  which  are  keyed  three  arms: 
The  lever  arm  A  to  which  the  lever  is  bolted;  the  link  arms  D  and  the  chair 


388  DETAILS  OF  PRACTICAL  MINING 

arms  E.  A  rod  R  connects  the  link  arms  of  the  two  chair  shafts  together. 
The  chair  arm  is  a  heavy  steel  casting  about  4  ft.  long.  To  the  upper 
end  of  the  chair  arms  are  bolted  the  chair  shoes  F,  which  are  moved  out 
over  channels  riveted  to  the  headframe  at  the  proper  height  for  landing 
the  cages.  On  the  inside  end  of  the  chair  shoe  is  a  hook  that  engages 
with  the  channel  on  which  it  slides  and  limits  the  inward  throw  of  the 
chairs. 

Skip  Dog  for  Inclined  Shaft  (By  Walter  R.  Hodge).— The  dog  illus- 
trated in  Fig.  310  is  used  in  the  London  and  Burra  Burra  shafts  of  the 
Tennessee  Copper  Co.  Both  these  shafts  dip  at  about  75°.  The  dog  is 


FIG.    310. CHAIN-OPERATED,    HINGED    SKIP   BEST. 

a  piece  of  oak,  8  X  8  in.,  stretching  across  the  compartment  and  resting 
on  and  hinged  to  the  dividers  between  the  compartments  below  the 
shaft  station.  The  hinges  are  strongly  made  of  ^  X  2-in.  strap  iron. 
When  not  in  use  the  dog  lies  back  and  out  of  the  path  of  the  skip,  clear- 
ing it  by  about  3  in.  Two  chains  encircle  the  dog  and  are  fastened  to 
an  eye-bolt  through  the  timber.  The  free  end  of  each  chain  reaches  to 
the  level  above.  When  it  is  desired  to  use  the  dog,  one  of  these  chains 
is  given  a  slight  pull  and  the  dog  rolls  over  on  its  hinges  and  takes  a 
position  across  the  shaft  in  the  path  of  the  skip.  To  clear  the  shaft  the 
other  chain  is  pulled. 

SKIP  DUMPS 

Angove  Skip  Dump. — The  skip-dumping  device  for  inclined  tracks 
invented  by  John  Angove  and  used  at  the  Copper  Range  shafts,  differs 
from  the  ordinary  type  of  dump  in  having  no  break  in  the  main  rails. 


SHAFT  CONVEYANCES  389 

Instead  of  the  front  wheels  of  the  skip  falling  away  on  the  bent-over  main 
rails  and  the  rear  wheels  continuing  up  on  auxiliary  rails  in  the  original 
direction,  the  front  wheels  continue  in  the  original  direction  and  the  rear 
wheels  are  elevated  on  auxiliary  rails  until  the  skip  assumes  a  dumping 
position.  A  great  advantage  of  the  dump  lies  in  the  fact  that  it  can 
be  applied  to  dumping  in  underground  bins  or  can  be  used  for  more 
than  one  dump  in  the  surface  bins  when  it  is  desired  to  hoist  both  waste 
and  ore.  Also,  it  can  be  arranged  to  intercept  a  skip  falling  back  from  a 
broken  rope  after  an  overwind. 

Referring  to  Fig.  311,  the  skip  is  shown  in  dumping  position  and  the 
action  of  the  auxiliary  tracks  is  apparent.  They  are  brought  down  out- 
side the  main  rails  and  the  wider  treads  of  the  rear  wheels  are  engaged 
by  them  while  the  narrower  front  wheels  pass  through.  The  connecting 
point  B  of  the  auxiliary  outside  rails  can  be  permanently  fastened  to  the 
lower  track  so  that  any  skip  passing  is  forced  to  dump,  or  it  can  be  hinged 
at  A,  as  shown  in  the  drawing,  in  which  case  the  dump  can  be  made 
operative  or  not,  as  desired.  When  open,  as  shown  in  the  dotted  posi- 
tion, the  skip  is  allowed  to  pass  through.  The  movable  point  B  has  a 
stud  C,  which  plays  in  a  slot  in  the  rocker-arm  D.  This  rocker-arm  and 
another  one  E,  are  attached  to  the  rocker-shaft  F.  By  depressing  E 
through  the  connections  shown,  the  switch  point  B  is  opened,  and  by 
raising  it  is  closed.  The  two  counterweights  G  and  H  make  the  move- 
ment of  the  operation  relatively  easy.  Inasmuch  as  no  shafts  can  ex- 
tend across  the  track  whore  the  skip  runs,  a  certain  portion  of  this 
mechanism  must  be  repeated  on  the  other  side. 

At  the  upper  part  of  the  auxiliary  tracks,  a  pocket  is  cut  in  the 
supporting  plate,  which  is  designed  to  catch  the  rear  wheels  of  a  skip  and 
prevent  its  descent  into  the  shaft  if  the  rope  should  break  for  any  reason. 
The  guard  rails  K  are  provided  to  keep  the  rear  wheels  in  their  proper 
position.  At  the  top  of  the  chute,  in  such  a  position  as  just  to  catch 
the  mouth  of  the  dumping  skip,  are  the  rollers  L,  which  prevent  the  front 
end  from  falling  down  and  binding  against  the  chute.  When  a  long  skip 
is  used,  the  hanging  opposite  an  underground  dump  may  have  to  be 
cut  away  to'get  room. 

Adjustable  Skip-dump  Plate  (By  W.  C.  Hart).— At  the  Wakefield 
iron  mine  in  Michigan  it  was  found  desirable  to  start  operations  with 
3-ton  skips  in  the  vertical  shaft,  these  being  most  suitable  for  the  initial 
hoisting  equipment  and  being  large  enough  to  handle  the  development 
production.  There  was,  however,  a  possibility  of  5-ton  skips  being  used 
at  a  future  stage  of  operations  and  it  was  decided  for  this  reason  to  design 
dump  plates  which  would  allow  changing  from  the  3-ton  to  the  5-ton  skips 
with  a  minimum  of  delay  and  labor.  Fig.  312  shows  a  pair  of  combination 
plates.  The  plates,  as  shown,  are  made  up  for  5-ton  skips.  To  get  them 


390 


DETAILS  OF  PRACTICAL  MINING 


ready  for  3-ton  skips  it  is  only  necessary  to  unbolt  the  roller  hub  A,  and 
bolt  it  into  position  shown  by  dotted  lines  B;  unbolt  the  13^-in.  length 
of  angle  between  C  and  D;  unbolt  the  manganese  point  C  and  bolt  it  in 
position  shown  by  dotted  lines  at  D.  The  change  can  easily  be  made  in  an 


FIG.    311. SKIP    DUMP    FOR    INTERMITTENT    SERVICE. 


hour,  between  shifts.  The  design  was  worked  out  graphically  on  a  large 
scale,  so  that  there  is  perfect  coordination  between  the  3-ton  skips  now 
in  use  and  the  plates.  The  guide  angles  at  the  tops  of  the  plates  provide 
for  overwinding  at  the  angle  of  discharge  of  the  skip,  and  there  is  no 
possibility  of  the  ore  dropping  back  into  the  shaft.  Runners  are  built  in 


SHAFT  CONVEYANCES 


391 


FIG.    312. DUMP    TO    ACCOMMODATE    EITHER   3-TON   OR   5-TON   SKIP. 


FIG.    313. ARRANGEMENT    FOR    CUTTING    SKIP    DUMP   IN   OR   OUT. 


392  DETAILS  OF  PRACTICAL  MINING 

the  headframe  at  the  upper  end  of  the  plates,  as  a  continuation  of  the 
guide  angles  of  the  plates,  so  that  the  skip  will  remain  at  the  angle  of  dis- 
charge for  an  overwind  of  10  ft. 

Compressed-air  Dump  Control  (By  J.  R.  McFarland). — The  Giroux 
Consolidated  Mines  Co.  at  Kimberly,  Nev.,  had  to  make  arrangements 
for  hoisting  both  ore  and  waste  with  the  same  skip  and  without  loss  of 
time  in  changing  from  one  to  the  other.  It  was  desired  to  avoid  wasting 
time  from  having  the  skip  dump  into  one  chute  and  having  a  man  climb  up 
into  the  headframe  and  adjust  a  gate  so  as  to  direct  the  material  into  the 
ore  bin  or  waste  bin  as  the  case  required.  Therefore  two  bins  were  built, 
the  lower  for  waste  and  the  upper  for  ore.  In  operation,  if  a  car  of  waste 
was  hoisted,  the  engineer,  by  the  operation  of  a  lever  at  his  side,  control- 
ling air  to  the  dump  machinery,  closed  a  switch  in  the  lower  dump  guide 
and  released  a  latch  on  the  skip,  allowing  the  skip  to  swing  at  its  center  on 
the  main  guide.  Thus  the  waste  was  dumped  into  the  lower  bin.  If  it 
happened  to  be  a  car  of  ore,  by  the  operation  of  the  same  lever,  he  opened 
the  switch  in  the  lower  dump  guide,  allowing  the  guide  wheel  to  pass 
through,  and  at  the  same  time  the  release  gib  was  held  closed  so  as  to 
maintain  the  upright  position  of  the  skip.  The  skip  thus  passed  through 
the  lower  dump  and  dumped  the  ore  into  the  upper  bin.  The  arrange- 
ment of  the  dump  mechanism  is  shown  in  Fig.  313. 

TRANSFERS 

Skip  and  Man -cage  Transfer  (By  Walter  R.  Hodge). — The  device 
herein  described  is  in  use  at  the  London  and  Burra  Burra  shafts  of  the 
Tennessee  Copper  Co.,  Ducktown,  Tenn.  At  these  shafts  men  are 
handled  in  one  only  of  the  three  compartments.  The  device  is  used  for 
swinging  skips  and  man  cages  in  and  out  of  the  shafts  when  it  becomes 
necessary  to  change  them. 

The  transfer,  Fig.  314,  consists  of  two  vertical  columns  of  extra- 
heavy  8-in.  iron  pipe,  on  each  of  which  swings  a  boom.  These  booms 
are  of  unequal  length  and  are  so  arranged  that  an  eye-bolt  near  the  end 
of  each  may  be  swung  over  the  center  of  the  compartment  in  which  the 
men  are  handled.  In  each  eye-bolt  are  hung  two  chains  with  hooks  at 
the  end.  These  hooks  engage  holes  in  the  sides  of  the  man-cage  and  of  the 
skip,  near  the  top  of  each.  The  booms  are  built  of  %-in.  plate  and  struc- 
tural steel.  They  rotate  about  the  columns  on  vertical  rollers  placed 
at  the  bottom  of  the  boom  on  the  side  of  the  column  from  which  the 
boom  extends,  and  on  the  other  side  at  the  top  of  the  boom.  A  collar 
bolted  below  each  boom  prevents  it  from  slipping  on  the  column.  About 
the  column  at  the  bottom  is  shrunk  a  heavy  cast-iron  base  which  is  in 
turn  bolted  to  a  concrete  base  or  pier.  Across  the  top  the  two  columns 


SHAFT  CONVEYANCES 


393 


are  joined  by  an  8-in.  channel  brace,  which  is  frequently  used  as  an  aid  in 
loading  material  in  the  skip  to  be  taken  underground.  The  whole  struc- 
ture is  stayed  by  four  steel  guy-ropes  fastened  to  convenient  "deadmen." 
In  operation,  when  it  becomes  necessary  to  exchange  skip  for  man 
cage,  the  skip  is  hoisted  into  position  near  the  long  boom,  the  bail  blocked 


-•S'Channe/ 


FIG,    314. COLUMNS    AND   BOOMS    FOR    CAGE    AND    SKIP    TRANSFER. 

with  a  length  of  drill  steel  to  prevent  its  dropping  down  and  the  chains 
attached  by  means  of  their  hooks  to  the  holes  in  the  sides  of  the  skip. 
The  cable  is  then  slacked  off  so  that  the  skip  swings  on  the  short  boom. 
The  bolt  is  removed  from  the  cable  clevis  and  the  skip  swung  out  of  the 
shaft  by  means  of  a  rope  reaching  the  ground  and  handled  by  the 
dumpers.  The  man  cage  is  swung  into  position  on  the  rails  by  means  of 
the  long  boom  on  which  it  is  already  suspended,  the  cable  is  attached  to 
the  bail,  the  cage  hoisted  and  the  chains  cast  off.  The  whole  operation 
occupies  about  two  minutes. 

Double  Skip-changing  Carriage  (By  William  Hambley  and  Albert 
E.  Hall) . — One  of  the  most  frequent  time  losses  in  hoisting  is  that  due  to 
changing  skips  for  one  reason  or  another,  often  for  repairs  to  the  skip  in 
use.  The  operation  of  changing  a  heavy  skip  without  any  device  other 
than  a  cradle  to  span  the  top  of  the  shaft  is  slow  and  uneconomical 
A  time-saving  device  for  this  operation  is  shown  in  Figs.  315  and  316. 
It  is  a  carriage  designed  to  hold  two  skips,  the  dimensions  given  being 
subject  to  alteration  as  the  case  demands. 


394 


DETAILS  OF  PRACTICAL  MINING 


In  the  installation  considered,  there  are  two  shafts  connected  by  a 
track,  which  also  runs  to  the  blacksmith  shop,  the  machine  shop  and  the 
repair  yard,  Fig.  315.  The  skip  carriage  is  designed  to  run  on  this  track, 
as  is  also  a  car  to  carry  drill  steel  from  the  blacksmith  shop  to  the  shafts. 


Machine 
Shop 


frown  Grtfcfe 


Repair  Tracks 


Blacksmith 

-Shop 
PLAN   OF    TRACK    ARRANGEMENT 


ShqftV 


^ 

Repair  Track  r 


Skip- rail  on  $ 
carriage 

SECTION  OF  WELL  AT  REPAIR  TRACK 
FIG.    315. PLAN    OF    SURFACE    ARRANGEMENTS    AND    REPAIR    WELL. 

A  small,  stationary  engine,  operated  by  air,  pulls  the  vehicles  by  means 
of  a  light  cable.  There  are  two  points  requiring  care  in  laying  the  track: 
First,  it  must  be  placed  far  enough  back  from  the  shaft  to  allow  the  nose 


p. 

~~*~  (fails  bored  at  ends  for 
y"  bolt,  used  as  block  •-  •' 
\_forsklp  wheels 

g 

rr 

^ 

T 

AT 

[ 

I 

V  ) 

" 

B 

"V 

J* 

} 

-• 

_:  '  '\ 

3" 

tj 

1          •   v 

BILL  OF  MATERIAL 

HARK.  NO.         DESCRIPTION 

A      5  i-&eams,5xlS'iong 
6      4  I-Beams.Sx  /8'  'long 

s 

FIG.    316. DESIGN    OF    THE    DOUBLE    CARRIAGE. 

of  the  skip  to  clear  the  timbers  supporting  the  shaft  guard  rails;  the  nose 
of  the  skip  will,  of  course,  project  some  distance  over  the  skip  carriage  if 
the  shaft  is  inclined.  Second,  the  track  at  the  shaft  should  be  laid  flush 
with  the  ground  to  avoid  the  danger  of  anyone's  tripping  on  it. and  plung- 
ing down  the  shaft.  The  carriage  itself,  Fig.  316,  is  made  as  low  as  pos- 


SHAFT  CONVEYANCES  395 


sible-,  so  that  tjie  center  of  gravity  will  be  low,  thus  reducing  the  tendency 
for  the  carriage  to  tip  up  as  a  skip  is  loaded  on  it  or  taken  off. 

A  skip  in  good  condition  is  always  kept  on  the  carriage.  When  it  is 
necessary  to  change  skips,  the  carriage  is  run  to  the  shaft,  the  skip  is 
hoisted  a  short  distance  above  the  surface  and  the  spanning  rails  thrown 
across  the  shaft.  The  skip  is  lowered  and  run  on  the  empty  half  of  the 
carriage.  The  carriage  is  then  advanced  a  few  feet,  the  new  skip  run  off 
and  connected  to  the  rope.  This  operation  takes  but  a  short  time  and 
is  much  easier  than  the  old  method,  requiring  eight  or  ten  men  with  bars. 
When  the  skips  have  been  changed,  the  carriage  is  run  to  the  repair  yard, 
the  old  skip  unloaded  and  a  new  one  put  on  ready  for  another  emergency. 

Skip  Transfer  at  Incline-shaft  Collar  (By  Arthur  C.  Vivian). — At 
the  conglomerate  shafts  of  the  Calumet  &  Hecla,  in  Michigan,  the  skips 
and  man  cars  when  not  in  use  are  stored  on  horizontal  tracks  in  a  detached 
building,  about  30  ft.  from  the  shafthouse  proper.  The  conveyances  are 
transferred  from  the  incline  tracks  of  the  skip  road  to  the  horizontal 
surface  tracks  over  short  pieces  of  track  curved  in  vertical  section,  which 
may  be  swung  into  place  for  that  purpose.  When  not  in  use  these  sec- 
tions of  auxiliary  track  must  be  out  of  the  way  of  skips  in  the  shaft,  and 
two  methods  of  disposing  of  them  are  employed,  the  choice  of  which 
depends  upon  the  weight  of  the  skip  used. 

The  simpler  and  more  convenient  of  the  two  methods  may  be  used 
only  with  a  small  skip,  this  for  the  reason  that  the  two  rails  have  no  lateral 
bracing  except  that  afforded  by  the  makeshift  wooden  prop,  and  a  heavy 
skip  would  be  likely  to  spread  the  rails  in  passing  over  them.  This  method 
is  shown  in  Fig.  317,  atl,  in  plan  only,  but  a  side  view  would  correspond 
except  in  details  to  the  side  view  of  the  other  method  shown  in  2.  Rails 
of  about  90  Ib.  weight  are  used,  and  they  are  not  reinforced  or  connected 
with  each  other  in  any  way  except  near  their  junctions  with  the  horizontal 
track,  where  they  are  both  pivoted  to  a  switch  bar  so  that  their  upper 
ends  may  be  swung  aside  horizontally  to  clear  the  skip.  The  switch  is 
used  to  make  connection  with  either  of  two  tracks,  one  holding  the  skip, 
the  other  the  man  car.  The  method  is  obviously  applicable  only  to  a 
single-skip-road  shaft,  as  there  would  not  be  room  between  the  adjacent, 
inside  rails  of  two-skip  roads  to  allow  the  auxiliary  rails  to  be  swung 
aside.  A  casting  riveted  to  each  rail  near  its  upper  end  projects  below 
it  and  engages  a  corresponding  slot  in  the  track  stringer  to  hold  the  rail 
in  place;  a  sprag  is  braced  against  each  rail  from  the  sides  of  the  shaft- 
house  to  prevent  the  rails  from  spreading.  The  rails  can  be  thrown  in 
and  out  of  position  easily  and  quickly  by  one  man,  and  it  is  unfortunate 
that  this  simple  method  is  not  of  wider  application. 

Where  heavier  skips  are  used  the  second  method  is  employed,  and 
this  conforms  in  principle  to  that  used  at  most  of  the  shafthouses  of  the 


396 


DETAILS  OF  PRACTICAL  MINING 


district.  The  two  rails  are  connected  rigidly  by  cross-braces,  and  they 
are  hinged  at  their  junction  with  the  horizontal  track  so  that  their  upper 
ends  may  be  lifted  high  enough  to  clear  the  skip.  The  method  is  illus- 
trated in  plan  and  side  elevation  in  2,  Fig.  317.  Most  shafthouses  are 
equipped  with  a  pony  winch  for  handling  timber  and  this  may  be  utilized 


K- 


-lron 
Shoe 


-Wooden 
Prop 


I. 


*':•  Incline 

/    Track 


Awf/7/crry  rail  in  position' 
for  changing  skip 


'Horizontal 
Tracks 


^.Casting  to 
''  engage  slot 

I  SIDE  SWINGING     RAILS 


Pivoted 

^'"Auxiliary  rail 
out  of  position 


Eyes  for  chain     ^\. 
to  hold  when 
raised  from  track 


8  Channels  •--> 


PLAN 


to  hold  track 
out  of  way  of  skip 


FIG.    317. ARRANGEMENTS    FOR    TRANSFERRING   VEHICLES. 

in  lifting  the  auxiliary  rails,  or  in  the  absence  of  this  accessory  they  may 
be  lifted  by  hand.  When  not  in  use,  they  are  suspended  by  chains  hung 
from  the  roof.  The  illustration  shows  a  heavy  rail  without  any  rein- 
forcement in  the  way  of  backing,  but  at  other  mines  it  is  usual  to  mount 
the  rail  for  part  of  its  length  on  a  wooden  stringer.  On  steeply  inclined 
tracks,  such  as  those  at  the  Allouez  shafts  and  Nos.  3  and  4  shafts  of  the 


SHAFT  CONVEYANCES  397 

Ahmeek,  where  the  track  is  inclined  at  80°,  this  reinforcement  takes  the 
form  of  guides  for  the  skip  wheels,  so  that  they  will  not  leave  the  track 
on  the  sharp  vertical  curve  used. 

Device  for  Holding  Skip  Rope  (By  L.  Hall  Goodwin). — The  device 
used  in  the  shafthouses  of  the  Quincy  Mining  Co.,  Hancock,  Mich.,  for 
holding  the  skip  rope  while  one  conveyance  is  being  substituted  for  another 
on  it,  has  advantages  over  the  cruder  methods  generally  employed. 


Hois+ing 
Cable 


FIG.    318. ROPE-HOLDING    APPARATUS. 

The  arrangement  consists  of  three  arms  rigidly  fixed  to  a  4-in.  round  iron 
bar.  The  two  arms  shown  in  Fig.  318  carry  the  holders  for  the  ropes, 
and  each  swings  in  an  arc  in  the  vertical  plane  which  contains  its  re- 
spective rope.  The  third  arm  lies  midway  between  the  other  two  and 
extends  beneath  the  concrete  floor,  a  slot  being  left  in  the  floor  to  allow 
the  arm  to  swing;  it  carries  a  counterbalancing  weight  and  also  serves  as 
a  lever  for  rotating  the  bar.  The  device  is  set  at  such  a  height  in  the 
shafthouse  relative  to  the  cranes  on  which  the  skips  and  man  cars  are 
stored  that  when  one  of  them  is  swung  into  position  over  the  track  it 
will  be  at  the  right  height  for  adjusting  the  clevis  to  the  rope  socket. 
When  a  conveyance  is  to  be  changed,  the  holder  is  swung  into  position 
by  rotating  the  arms  until  the  holder  engages  the  hoisting  rope.  The 
rotation  is  accomplished  by  means  of  a  small  hand  winch  which  winds  a 
chain  attached  to  the  counterbalance  arm.  On  either  end  of  the  winch 


398  DETAILS  OF  PRACTICAL  MINING 

drum  is  a  ratchet  wheel,  one  of  which  holds  the  arms  when  in  position, 
the  other  when  out  of  position.  The  illustration  shows  the  manner  in 
which  the  holder  catches  the  rope.  For  convenience  one  holder  is  shown 
empty,  the  other  engaging  a  rope.  As  a  matter  of  fact  the  arms  are  in 
the  position  assumed  when  they  are  out  of  service;  they  are  swung  up 
when  they  are  to  be  used. 

BUCKETS 

Joplin  Ore  Buckets. — In  the  Joplin  district  of  Missouri  practically 
all  the  ore  is  hoisted  in  buckets.  These  buckets,  or  cans  or  tubs,  as  they 
are  commonly  called,  are  made  with  straight  sides.  The  ears  are  welded 
to  straps  instead  of  being  riveted  to  the  sides.  The  buckets  are  used 
without  a  crosshead  to  guide  them  through  the  shaft,  and  so  have  to 
stand  much  rough  usage.  They  are  made  with  a  bottom  flange,  Fig.  319, 
about  13/2  m-  deep  so  that  they  will  rest  flat  upon  the  tub  cars.  On  the 
bottom  there  is  a  cross-strap  riveted  to  another  strap  inside.  This  dis- 
tributes the  strain  of  the  pull  from  the  bottom  ring  while  dumping  the 
bucket  at  the  surface.  The  side  straps  also  are  riveted  to  stiffening 
straps  on  the  inside  while  the  ears  are  of  IJ^-in.  Norway  iron  welded  to 
the  2%  X,  J^-in.  side  straps.  The  bail  is  of  1^-in.-  Norway  iron  and  is 
V-shaped  with  a  slight  curve  at  the  apex  for  the  reception  of  the  hook. 
This  bail  is  made  with  the  hooks  turned  in  so  as  to  be  less  liable  to  catch 
on  timbers  during  hoisting. 

Usually  the  side  straps  come  down  and  turn  up  so  as  to  hook  over  the 
flange  at  the  bottom,  thus  throwing  the  weight  of  part  of  the  load  on  the 
hook  as  well  as  on  the  three  rivets  by  which  the  side  straps  are  attached 
to  the  bucket.  But  in  the  case  of  the  buckets  at  the  Oronogo  Circle 
mine  the  bottom  straps  run  up  the  sides  about  a  foot  and  are  overlapped 
by  the  side  straps  to  which  they  are  riveted,  as  illustrated.  In  this  way 
the  strain  of  dumping  is  taken  from  the  bottom,  which  already  takes  the 
most  of  the  wear  and  tear  of  usage,  and  is  thrown  on  the  sides.  A  slight 
drawback  is  that  the  whole  weight  of  the  load  is  thrown  on  the  three 
rivets  of  the  side  straps.  At  the  Underwriters  mine,  commonly  called 
the  Yellow  Dog,  an  extra  piece  of  iron  is  put  in  under  the  bottom  strap, 
as  shown,  to  keep  the  ring  from  punching  a  hole  through  the  bottom  of  the 
bucket. 

In  most  of  the  buckets  used  in  the  Joplin  district  the  bottom  is  only  a 
sheet  of  No.  8  iron.  To  protect  this  from  wear  the  shovelers  are  made  to 
throw  in  fine  dirt  at  first,  and  then  after  a  protecting  layer  has  been  formed 
on  the  bottom,  the  boulders  are  loaded.  In  the  case  of  the  Federated 
Zinc  Co.  and  a  few  others,  tubs  with  wooden  bottoms  are  used.  This 
wooden  bottom  of  2-in.  oak  is  protected  from  the  cutting  of  the  boulders 
by  a  plate  of  No.  10  iron,  and  seems  to  be  serviceable.  The  flange  at  the 


SHAFT  CONVEYANCES 


399 


400  DETAILS  OF  PRACTICAL  MINING 

bottom  of  the  bucket  becomes  battered  in  the  course  of  time.  In  one 
instance  instead  of  flanging  the  bottom  plate,  buckets  were  made  with 
an  angle-iron  ring  riveted  to  the  sides  at  the  bottom.  The  bottom  plate 
then  rested  on  this  angle,  but  such  buckets  are  much  more  expensive  to 
make  than  are  those  of  the  flange  type. 

Owing  to  the  fact  that  the  hoisting  is  done  without  a  crosshead,  the 
buckets  often  catch  on  the  cribbing  timbers.  On  that  account  the  top  of 
the  bucket  is  reinforced  by  a  band  of  2J^  X  J^-in.  iron.  A  few  buckets 
are  built  with  side  stiffeners  put  in  half  way  between  the  side  straps. 
These  run  vertically  from  top  to  bottom  of  the  bucket  and  are  turned  over 
to  form  a  hook  over  the  top  band  as  well  as  at  the  bottom  flange.  As 
these  extra  side  straps  are  riveted  to  the  top  band  there  is  less  danger  that 
the  bucket  may  bend  out  of  shape  when  it  catches  on  the  timbers  in  the 
shaft.  But  the  main  advantage  is  that  the  bucket,  in  landing  on  the  plat 
at  the  bottom  of  the  shaft  strikes  on  these  side  straps;  consequently  the 
flange  is  less  liable  to  be  bent. 

In  many  instances,  the  bottom  strap  is  extended  clear  across  the 
bottom  and  caught  in  under  the  turn-up  of  the  ear  straps.  This  seems 
to  be  the  best  way  of  putting  on  the  bottom  strap,  since  part  of  the  strain 
is  thrown  on  the  side  straps  while  the  bucket  is  being  dumped  and  taken 
off  the  bottom  strap,  but  it  is  not  commonly  done  as  the  bucket  is  slightly 
harder  to  make.  Probably  the  best  bucket  is  obtained  by  toeing  the 
bottom  strap  under  the  hook  of  the  ear  straps,  using  a  wooden  bottom, 
and  putting  in  the  extra  side  straps  already  mentioned.  But  there  is  the 
drawback  that  this  makes  the  bucket  somewhat  heavier  and  more  awk- 
ward for  the  hooker  to  handle  when  he  changes  buckets  at  the  bottom  of 
the  shaft.  Moreover,  it  is  somewhat  more  costly  in  upkeep.  In  case 
a  wooden  bottom  is  not  used,  it  is  well  to  put  in  the  extra  strap  so  as  to 
protect  the  bottom  from  wear  by  the  ring.  Such  a  bucket  combining  the 
good  points  of  several  of  the  "tubs"  in  use  in  the  Joplin  district  is  shown 
in  the  illustration. 

These  tubs  or  buckets  are  made  in  certain  standard  sizes .  The  largest 
buckets  used  in  the  Joplin  district  are  those  at  the  Davey  mines  of  the 
American  Zinc,  Lead  &  Smelting  Co.  These  are  34  in.  in  diameter  and 
34  in.  high.  They  hold  as  loaded  about  1200  lb.,  but  at  the  rating  placed 
on  buckets  in  the  district  these  large  buckets  would  be  called  1600-lb. 
cans.  The  most  commonly  used  sizes  are  the  30  X  30-in.  buckets,  with 
30  X  28-in.  and  28  X  30-in.  close  seconds,  the  diameter  being  given  first 
in  all  cases.  These  are  called  1200-lb.,  large  1000-lb.  and  small  1000-lb. 
cans,  respectively.  Other  sizes  are  26  X  28-in.  called  850-lb.,  24  X  28- 
in.  rated  at  750-lb.,  and  22  X  26-in.  rated  at  500-lb.  In  some  instances 
28  X  32-in.  and  30  X  32-in.  as  well  as  32  X  34-in.  tubs  have  been  used. 

None  of  these  buckets  holds  what  it  is  rated  at,  for  they  are  rarely 


SHAFT  CONVEYANCES  401 

filled  more  than  four-fifths  full.  In  mining,  the  ore  breaks  in  many 
boulders,  especially  in  the  case  of  the  stope  holes,  so  that  there  is  much 
empty  space  in  the  buckets.  Indeed,  it  is  necessary  to  keep  a  close 
watch  upon  the  shovelers  to  prevent  them  from  building  "windies,"  as 
they  are  called  in  the  district,  by  piling  the  boulders  into  the  tubs  in  such 
a  manner  as  to  leave  a  large  percentage  of  the  tub  unfilled.  The  larger 
the  diameter  of  the  bucket,  the  more  difficult  it  is  to  build  these  "  windies; " 
hence  it  is  better  to  use  either  a  30  X  30-in.  or  30  X  28-in.  than  a  28  X 
30-in.  bucket,  especially  when  mining  the  deposit  by  a  "stope."  The 
real  amount  that  these  different  buckets  hold  depends  upon  the  richness 
of  the  ore  which  to  a  large  extent  governs  the  fineness  to  which  the  ore 
breaks,  and  also  upon  whether  the  ore  comes  from  a  stope  or  a  heading. 
The  30  X  30-in.  cans  which  are  rated  at  1000-lb.  capacity  throughout 
the  district  have  been  found,  in  many  instances  when  their  contents  were 
weighed,  to  hold  about  850  Ib.  on  an  average  when  loaded  with  dirt 
broken  fine  from  a  heading,  while  the  buckets  that  were  loaded  from  the 
stope  piles  weighed  only  800  Ib.  Many  of  the  operators  in  the  district 
make  such  allowances  in  calculating  their  yield  and  their  costs,  but  some 
use  the  rated  capacities. 

Bucket  for  Lowering  Drill  Steel  (By  Evans  W.  Buskett).— In  the 
practice  of  underhand  stoping  in  the  sheet-ground  mines  in  the  Joplin 
district,  drill  bits  sometimes  reaching  a  length  of  16  ft.  are  used.  To  send 
such  drill  steel  the  special  steel  can,  shown  in  Fig.  320,  was  devised.  The 
bucket  proper  is  about  24  in.  in  diameter  and  30  in.  deep.  In  the  center 
is  a  cylinder  about  9  in.  in  diameter  passing  through  the  bottom  of  the 
can  and  braced  at  the  top  as  shown.  This  cylinder  can  be  made  to  suit 
the  length  of  steel  used.  The  sketch  shows  a  cylinder  for  16-ft.  drills. 
In  use  the  can  is  set  in  a  hole  in  the  platform  at  the  collar  of  the  shaft  and 
the  steel  is  placed  in  it.  The  longer  pieces  are  placed  in  the  cylinder  while 
the  short  ones  are  placed  in  the  compartments  made  by  the  braces. 
When  the  can  reaches  the  bottom  of  the  shaft  it  is  laid  on  its  side  and  the 
rope  detached. 

Man  Platform  and  Bucket  Crosshead  (By  E.  M.  Hobart).— In 
many  isolated  mines  where  hoisting  buckets  are  used,  safety  crossheads 
cannot  be  obtained  on  short  notice.  In  such  cases  the  crosshead  shown  in 
Fig.  321  has  advantages  for  temporary  use.  One  occasion  arose  when  it 
was  necessary  to  demolish  a  wooden  headframe  over  a  1400-ft.  shaft,  in 
order  to  erect  a  steel  structure  in  its  place  and  at  the  same  time  retimber 
the  shaft.  One  sheave  was  placed  on  the  center-post  section  of  the  old 
frame,  which  sufficed  as  a  temporary  frame  with  the  addition  of  a  few 
braces,  but  was  not  strong  enough  to  support  a  cage.  The  addition  of  a 
platform,  as  shown  in  the  illustration,  to  the  crosshead,  solved  the  prob- 
lem .of  lowering  men.  The  platform  accommodated  six  men,  and  the 

26 


402 


DETAILS  OF  PRACTICAL  MINING 


FIG.    320. DRILL-STEEL  BUCKET   WITH    LONG    CENTRAL    SECTION. 


K-      — < 

FIG.    321. BUCKET    CROSSHEAD    WITH    PLATFORM    FOR    LOWERING   MEN. 


SHAFT  CONVEYANCES 


403 


bucket  was  attached  to  a  chain  below  the  crosshead  sufficiently  long  to 
lower  15-ft.  timbers. 

Rapid  and  Safe  Bucket  Connection  (By  Joseph  Goldsworthy). — 
Fig.  322  shows  a  connecting  pin  for  sinking  buckets,  which,  although  not 
new,  has  proved  safe,  quick  and  simple  in  practice,  and  which  obtains  the 
confidence  of  the  miners.  No  dimensions  are  given,  as  these  will  vary  in 
almost  every  case;  for  a  %-in.  rope,  there  would  be  used  a  1^-in.  pin 


FIG.    322. — LUG    PIN   FOE   CLEVIS    OF  BUCKET. 


with  two  lugs,  which  are  %  X  %  in.  by  J^  in.  long.  A  slot  is  cut  in  the 
top  of  the  pin  hole  through  the  jaws  of  the  clevis  socket,  as  shown.  The 
slots  are  just  large  enough  to  take  the  lugs  with  sufficient  clearance  so 
that  the  pin  can  be  quickly  placed  in  position.  The  distance  from  inside 
to  inside  of  the  lugs  should  be  slightly  greater  than  the  distance  from  out- 
side to  outside  of  the  jaws  of  the  socket.  It  will  be  seen  that  the  front  lug 
is  on  .top  of  the  pin,  and  the  back  lug  on  the  bottom.  The  pin  is  inserted 
by  pushing  the  top  lug  through  both  slots,  giving  the  pin  a  half  turn  so  as 
to  bring  the  last  lug  on  top,  pushing  this  lug  through  one  slot  and  giving 
the  pin  another  half  turn,  bringing  it  to  the  proper  position,  as  shown.  It 
will  be  readily  seen  that  the  chances  of  the  pin's  working  out  are  remote; 


404  DETAILS  OF  PRACTICAL  MINING 

it  would  have  to  make  a  half  turn  to  get  the  back  lug  into  line  with  its 
slot,  then  travel  endwise  to  get  this  lug  to  the  outside  of  the  jaw;  at  this 
point  the  front  lug  would  be  on  the  bottom  of  the  pin,  and  would  be  hold- 
ing, so  that  the  operation  would  have  to  be  repeated  before  the  pin  could 
fall  entirely  out.  The  pin  is  simple,  without  working  parts  to  get  out  of 
order,  or  to  clog  with  dirt,  and  in  changing  buckets,  connections  are  made 
as  quickly  with  this  device  as  with  any  other. 

BUCKET  DUMPS 

Joplin  Method  of  Dumping  Buckets. — The  following  method  of 
dumping  buckets  is  practised  in  the  Joplin  district  when  tramming  the 
ore  on  the  surface  to  a  bin  near-by,  as  when  the  ore  is  being  hand  jigged,  or 
for  dumping  buckets  of  waste  as  in  shaft  sinking.  The  shaft  is  straddled 
by  truck  tracks  which  are  laid  with  a  wide  enough  gage  so  that  the  bucket 
will  come  up  between  the  rails  without  hitting.  On  the  truck  is  nailed  a 
2-in.  cleat  against  which  the  front  side  of  the  bucket  rests  when  it  is  landed 
on  the  car,  while  at  the  back  end  is  a  4  X  6-in.  timber  also  nailed  to  the 
deck.  On  top  of  this  back  piece  the  rear  end  of  the  bucket  rests  in  a 
tilted-forward  position.  The  track,  when  tramming  to  a  near-by  mill, 
generally  has  a  considerable  grade  so  that  the  trammer  can  ride  the  truck 
out  to  the  dump.  He  gets  up  such  speed  to  the  load  that  when  it  strikes 
the  cribbing  of  the  dump  the  momentum  causes  the  bucket  to  tilt 
forward.  During  this  tilting  the  bucket  is  generally  guided  by  the  man, 
while  at  the  same  time  he  gives  the  bucket  a  slight  push  forward  just  as  it 
strikes  the  dump,  so  as  to  aid  in  unsetting  in  case  the  momentum  of  the 
load  is  not  enough.  The  buckets  on  which  these  dumps  are  worked 
generally  are  not  larger  than  about  22  X  30  in.  A  tall  can,  of  course, 
works  better  than  one  with  breadth  equal  to  height. 

The  dump  is  a  crib  built  up  on  the  bin  or  the  tracks  to  approximately 
the  height  of  the  top  of  the  bucket  car,  about  15  in.  This  crib  is  securely 
tied  in  place  so  that  the  shock  of  the  constant  bumping  will  not  move  it 
and  the  crib  timbers  are  securely  spiked  together  so  as  to  stand  the  work. 
The  crib  is  about  the  same  width  as  the  track,  or  several  inches  wider 
than  the  bucket,  so  that  provision  is  made  for  side  swing  during  the  tipping 
of  the  bucket.  In  the  direction  in  which  the  bucket  dumps,  the  crib  is 
somewhat  greater  than  the  width  of  the  bucket,  yet  less  than  the  diagonal 
of  the  longitudinal  section  of  the  bucket.  Consequently,  in  dumping^ 
the  top  of  the  rim  of  the  bucket  strikes  on  the  far  side  of  the  crib  while 
the  lower  part  of  the  side  of  the  bucket  is  resting  upon  the  near  side  of  the 
crib.  This  throws  the  bucket  into  an  inclined  position  and  the  rock  or  ore 
slides  out  aided  by  its  momentum.  Owing  to  the  roughness  of  the  crib 
walls  it  is  impossible  for  the  bucket  to  go  down  through,  although 


SHAFT  CONVEYANCES  405 

the  section  of  the  dump  crib  is  greater  than  the  bottom  section  of  the 
bucket. 

In  some  instances  these  dumps  are  rigged  so  as  to  allow  side  dumping 
of  the  car.  The  cribbing  is  then  built  alongside  the  track,  with  a  bump- 
ing block  fixed  across  the  track  to  stop  the  car  even  with  the  dump  crib. 
But  in  this  form  no  aid  comes  from  the  momentum  of  the  load  and  the 
block  on  the  back  of  the  car  truck  has  to  be  made  so  as  to  throw  the 
bucket  into  practically  a  balanced  position  with  the  top  pointing  to  the 
side  on  which  the  can  is  to  be  dumped ;  then  with  a  slight  push  the  tram- 
mer can  dump  the  bucket.  This  dumping  system  is  surprisingly  simple 
and  effective.  Flying  dumps  are  generally  made,  since  they  are  easier  on 
the  man,  and  seldom,  if  ever,  does  the  bucket  fail  to  take  the  dump  prop- 
erly. In  getting  the  bucket  back  on  the  car,  all  that  is  necessary  is  to 
tip  it  straight  back  the  way  it  came  over  and  slide  it  back  a  few  inches  so 
that  its  front  is  behind  the  forward  cleat. 

Device  for  Bucket  Dumping  (By  J.  R.  McFarland). — An  ingenious 
dumping  arrangement  is  employed  at  a  Nevada  mine.  Hoisting  is  con- 
ducted with  a  bucket,  and  it  is  customary  to  keep  the  collar  of  the  shaft 
closed  with  hinged  doors,  except  when  the  bucket  is  passing  through. 
To  manipulate  these  doors  and  dump  the  bucket,  either  necessitated  the 
employ  of  an  extra  man  at  the  shaft,  or  made  a  large  amount  of  additional 
work  for  the  hoistman  in  running  back  and  forth  between  the  hoist  and 
the  shaft.  Four  round  trips  were  required  on  his  part  for  each  hoisting 
trip,  as  follows :  To  shaft  to  open  doors,  to  engine  to  raise  bucket,  to  shaft 
to  insert  dumping  hook,  to  engine  to  dump,  to  shaft  to  detach  hook,  to 
engine  to  lower  bucket,  to  shaft  to  close  doors,  to  engine  to  await  next 
trip.  This  extra  work  was  eliminated  by  the  use  of  the  devices  illus- 
trated in  Fig.  323. 

On  receiving  the  signal  to  hoist,  the  engineer  releases  the  lower  rope. 
This  allows  the  counterweights  to  pull  the  chute  up  and  away  from  the 
shaft,  the  chute  being  pivoted  at  A.  The  chute  pulls  with  it  the  sliding 
rods  B,  just  above  the  collar,  which  by  means  of  connecting  arms  opens 
the  doors  C.  The  bucket  is  then  hoisted  until  the  crosshead  passes  above 
the  pins  set  in  the  guides  at  D.  The  upper  rope  is  next  pulled  by  the 
engineer,  throwing  in  the  pins  against  the  force  of  the  springs  shown  in  the 
drawing.  The  bucket  is  lowered  until  the  crosshead  rests  on  the  pins  and 
holds  them  in  position.  The  lower  rope  is  pulled,  bringing  the  chute  into 
position  under  the  bucket  and  closing  the  doors.  The  chute,  in  swinging 
over,  catches  the  tail  chain  of  the  bucket  in  a  notch  in  its  upper  end. 
The  bucket  is  lowered  and  is  dumped  as  shown,  the  tail  chain  preventing 
it  from  sliding  in  the  chute  without  dumping.  The  bucket  is  hoisted,  and 
as  soon  as  the  crosshead  is  lifted  from  the  pins,  the  springs  force  them  back. 
The  lower  rope  is  released  again,  swinging  the  chute  out  of  the  way  and 


406 


DETAILS  OF  PRACTICAL  MINING 


opening  the  doors.  The  bucket  and  crosshead  are  lowered  and  the  doors 
closed.  Different  arrangements  of  the  counterweights  from  that  shown 
can,  of  course,  be  used. 

Automatic   Bucket   Tipple    (By   D.    A.  Cavagnaro). — The  Channel 
Mining  Co.,  of  San  Andreas,  Calif.,  has  installed  an  ingenious  device 


FIG.    323. ARRANGEMENT   FOR    DUMPING   BUCKET    WITHOUT    LEAVING    HOIST. 

which  permits  the  hoisting  engineer  to  dump  a  hoisted  bucket  without 
leaving  his  engine.  Referring  to  Fig.  324,  the  lower  side  view  shows  the 
tipple  with  the  bucket  in  place.  The  upper  side  view  shows  the  dumping 
position.  The  top  plan  shows  the  bucket  in  the  tipple  but  not  the  catches 
or  the  rotating  control.  The  back  view  shows  the  tipple  without  the 
bucket. 

The  tipple  itself  is  built  around  four  upright  pieces,  P,  which  are  bev- 


SHAFT  CONVEYANCES 


407 


eled  to  permit  the  entrance  of  the  bucket.  On  the  sides  }/£  X  6-in.  iron 
straps  I  are  bolted  to  the  uprights.  The  top  of  the  back  is  closed  by 
two  2  X  12-in.  planks  L.  The  iron  hook  B  is  bolted  to  these  and  also  any 


SIDE  ELEVATION 


SIDE  ELEVATION  REAR  ELEVATION 

FIG.    324. DEVICE    FOR   DUMPING   BUCKET. 


weights  which  may  be  necessary  to  hold  the  tipple  upright.     The  bottom 
is  closed  by  a  %  X  24  X  30-in.  iron  sheet  K,  through  which  the  latch  A 


408  DETAILS  OF  PRACTICAL  MINING 

works.  The  latch  is  held  inside  the  tipple  by  the  spring  H  and  from  its 
upper  end  0  a  rope  M  leads  to  the  hoist.  The  latch  A  works  on  the  1 J^- 
in.  round  iron  N,  which  extends  to  the  sides  far  enough  to  rest  on  the 
timbers  C,  and  thus  supports  the  tipple.  To  the  sides  of  the  tipple  are 
bolted  iron  plates  which  carry  two  half-circles  E  with  a  radius  of  18  in., 
made  of  2^  X  2J^-in.  angle  iron,  and  in  these  are  set  a  number  of  teeth. 
These  teeth  are  spaced  3  in.  apart  and  are  1  in.  from  the  outer  edge. 
The  inner  teeth  are  about  1  in.  long,  but  the  outer  two  teeth,  J  and  R,  are 
curved,  about  3  in.  long,  and  riveted  in  square  holes  to  prevent  turning. 
These  teeth  mesh  into  holes  in  the  horizontal  plates  Q,  fastened  to  the 
timbers  C.  The  tipple  at  rest  pivots  on  the  teeth  R,  and  the  half  circle 
is  so  set  that  the  pivot  point  is  about  6  in.  behind  the  center,  which  ar- 
rangement causes  the  forward  dumping  movement.  In  operation  the 
bucket  is  hoisted  into  the  tipple  by  the  engineer  and  forces  back  the  latch 
A,  which  then  springs  in  again  and  catches  the  bottom  of  the  bucket. 
When  the  rope  is  slacked,  the  device  tips  forward  by  its  own  weight,  the 
operation  being  controlled  by  the  teeth  of  the  half-circle  E  meshing  into 
the  holes  in  Q,  and  the  contents  of  the  bucket  discharge  into  the  ore  chute. 
The  bucket  is  prevented  from  sliding  out  while  tipped,  by  the  hook  B. 
When  empty,  the  engineer  pulls  the  tipple  back  to  an  upright  position  by 
means  of  the  hoisting  rope  and  by  pulling  the  rope  M ,  releases  the  latch  A 
and  permits  the  bucket  to  descend.  As  the  tipple  is  not  fastened  to  the 
timbers  C,  it  could  be  pulled  through  by  the  bucket  but  for  the  timbers  G, 
which  catch  the  back  edge. 

Bucket-dumping  Device  (By  Harold  A.  Linke). — A  safe  and  service- 
able device  for  dumping  buckets  at  the  collar  of  a  shaft  during  sinking 
operations  is  constructed  as  follows:  A  chute  A,  Fig.  325,  is  built  of  2  X 
10  plank,  the  width  depending  on  the  size  of  the  bucket  used.  The  sketch 
shows  a  convenient  size  for  use  with  a  bucket  of  9-cu.  ft.  capacity.  The 
floor  is  laid  diagonally  and  doubled,  one  set  of  plank  crossing  the  other  at 
acute  angles,  as  shown  at  F.  The  sides,  two  planks  high  and  of  single 
thickness,  are  reinforced  with  cleats  and  strap  iron.  The  chute  is  hinged 
at  B.  At  the  center  of  the  chute  at  the  upper  end  a  slot  H  is  cut  about  12 
in.  long  and  2J4  in.  wide,  reinforced  around  the  top  and  bottom  edges 
with  bands  of  strap  iron  bolted  together  through  the  flooring.  C  repre- 
sents a  counterbalance  to  assist  in  raising  and  lowering  the  chute.  When 
the  filled  bucket  reaches  the  collar  of  the  shaft  it  is  hoisted  high  enough  to 
clear  the  chute,  which,  being  raised,  is  in  position  K.  As  the  bucket  is 
then  slowly  lowered  the  topman  simultaneously  lowers  the  chute.  A 
6-in.  plate  of  %-in.  iron  fastened  to  the  end  of  a  chain  (about  21  in.  long) 
suspended  from  the  bottom  of  the  bucket  is  caught  in  slot  H.  The  bucket 
and  chute  are  then  slowly  lowered  until  the  top  of  the  chute  strikes  the 
bumper  D.  As  the  bucket  is  lowered  for  dumping,  the  curved  block  Et 


SHAFT  CONVEYANCES 


409 


gouged  somewhat  in  the  center  to  fit  the  bucket  and  thus  preventing 
lateral  motion,  raises  the  bottom  end  of  the  bucket  high  enough  to  allow 
the  contents  to  be  completely  removed.  After  dumping,  the  topman 
raises  the  chute  while  the  bucket  is  being  swung  clear,  by  pulling  down- 
ward on  the  rope  G.  An  important  detail  to  be  observed  in  building  a 
dumping  chute  of  this  sort  is  to  make  the  block  E  about  15  in.  long,  curved 
as  sketched  and  gouged  to  prevent  the  rolling  motion  of  the  bucket.  Five 
strips  of  strap  iron  should  be  securely  fastened  on  the  block  for  the  bucket 


FIG.    325. SWINGING    CHUTE    FOR   DISCHARGING   BUCKET. 

bottom  to  slide  on,  facilitating  dumping  and  affording  protection  against 
wear.  The  iron  strips  should  be  occasionally  greased.  It  is  advisable 
to  board  up  the  bent  on  the  car  side  of  the  shaft,  as  shown  at  J,  to  pre- 
vent dirt  from  dropping  down  the  shaft. 

Automatic  Water  Bucket  Dumper  (By  Algernon  Del  Mar). — When 
hoisting  water  from  vertical  shafts  by  means  of  a  bucket,  it  is  usual  to 
have  a  man  attend  to  the  dumping  at  the  collar  of  the  shaft.  The 
arrangement  shown  in  Fig.  326,  used  at  the  shaft  of  the  Bishop  Creek 
Milling  Co.,  in  California,  dispenses  with  the  extra  man,  so  that  the 
hoisting  engineer  attends  to  the  whole  operation,  the  device  being  auto- 
matic. The  discharge  trough  D  is  stationary,  the  portion  E  being 
hinged.  In  .the  position  illustrated,  the  bucket  although  not  shown,  is 
supposed  to  be  resting  on  E,  and  is  dumping  the  water  through  a  bottom 
valve.  The  engineer  hoists  the  empty  bucket,  which  strikes  the  cross- 
head  H.  The  crosshead  cannot  descend  below  the  stops  K.  As  the 
crosshead  is  raised,  it  pulls  the  rope  C,  which  lifts  E  to  a  vertical  position, 
where  it  is  held  by  the  weight  F.  When- the  engineer  hoists  the  full 


410 


DETAILS  OF  PRACTICAL  MINING 


bucket,  it  strikes  the  crosshead  and  pulls  on  the  rope  A,  which  is  connected 
to  the  crosshead  and  to  E  over  a  pulley,  again  lowering  the  trough  into  the 
position  shown;  the  weight  F  is  not  heavy  enough  to  raise  the  trough 
alone.  The  ropes  A  and  B  for  convenience  should  be  on  the  opposite  side 


FIG.    326. SELF  DISCHARGING  BAILING   BUCKET. 

of  the  trough  from  C.     The  rope  A  is  long  enough  to  allow  E  to  be  vertical 
without  pulling  on  the  crosshead. 

Dumping  Arrangement  in  Sinking  (By  L.  D.  Davenport). — Fig.  327 
shows  an  arrangement  for  carrying  a  sinking  bucket  clear  of  the  shaft. 
Two  hangers  of  %  X  3-in.  flat  iron  are  bent  at  90°,  6  in.  from  their  upper 
ends,  and  are  fastened  by  J^-in.  bolts  to  one  of  the  12  X  12-in.  timbers 
under  the  sheave  wheel.  The  hangers  support  a  1  X  4-in.  rail,  the  upper 
corners  of  which  are  slightly  chamfered  to  lessen  the  wear  on  the  8-in. 
sheave  which  travels  over  it.  There  are  three  bolt-holes  in  the  lower 
end  of  the  hangers  spaced  3  in.  so  that  the  inclination  of  the  rail  may  be 
changed;  as  shown,  it  slopes  2%  in.  to  the  foot.  A  "grab  link"  is  sus- 
pended from  the  8-in.  sheave  by  a  yoke  of  J/£  X  3-in.  flat  iron,  and  a  short 
piece  of  chain  with  a  hook  at  its  lower  end  is  caught  into  the  grab  link.  A 
latch,  made  of  %  X  3-in.  stock,  bent  as  shown,  is  fastened  by  a  %-in.bolt 
to  the  hanger  near  the  hoisting  rope.  A  bumper  curved  to  fit  the  sheave 


SHAFT  CONVEYANCES 


411 


is  fastened  to  the  other  hanger  by  a  short  L-shaped  bracket.  In  operation 
the  bucket  is  hoisted  until  the  hook  on  the  chain  from  the  grab  link  can  be 
caught  into  the  bail.  The  bucket  is  then  lowered,  the  latch  released  and 
the  small  sheave  carrying  the  bucket  rolls  down  to  the  bumper.  This 


FIG.    327. TROLLEY    HOOK    FOR    SINKING   BUCKET. 

movement  carries  the  bucket  clear  of  the  shaft  and  directly  over  a  small 
car  on  the  surface.  The  bucket  is  dumped,  the  hoist  started  and  the 
traveling  sheave  returned  to  its  original  position,  where  it  is  held  by  the 
latch.  The  chain  is  then  unhooked  and  the  bucket  lowered  into  the  shaft. 


,  *4  Brackets 

Section    A~B 
Over  all  Itnf+b  of  Chute,  8ft. 

FIG.   328. — SLIDING   CHUTE   FOR  BUCKET   DUMP. 

Sliding  Chute  for  Sinking  (By  L.  D.  Davenport). — Fig.  328  shows  a 
sliding  chute  in  common  use  in  the  Lake  Superior  iron  country  for  shaft- 
sinking  operations.  The  apparatus  is  operated  by  one  lander  as  follows : 
The  sinking  bucket  is  hoisted  just  high  enough  to  clear  the  rear  end  of  the 
chute  and  the  latter  is  pulled  back  under  the  bucket  until  the  wheels  strike 
the  crosshead  guides.  The  bucket  is  dumped  into  the  chute  and  the  dirt 
and  rock  run  into  the  tram  car  below.  The  chute  is  then  pushed  ahead 
clear  of  the  shaft  and  the  bucket  is  lowered.  With  a  little  practice,  this 


412  DETAILS  OF  PRACTICAL  MINING 

operation  is  done  quickly.  The  chute  is  sufficiently  long  so  that  in  case 
the  bucket  gets  away  from  the  lander  and  dumps  backward,  as  sometimes 
happens,  no  dirt  falls  into  the  shaft.  The  chute  is  8  ft.  long  over  all  and 
is  built  of  J^-in.  iron  plates  stiffened  with  iron  straps.  The  side  plates 
are  fastened  to  the  bottom  plate  with  2  X  3-in.  angles  riveted  as  shown. 
The  front  end  is  1  ft.  9  in.  below  the  rails  which  carry  it  and  about  1  ft. 
above  the  top  of  the  tram  car  at  the  shaft  collar.  This  brings  the  chute 
track  about  7  ft.  above  the  collar  of  the  shaft.  Timber  is  brought  in  at 
the  opposite  side  of  the  shaft  from  the  tram  car  and  since  the  gage  of  the 
chute  track  is  the  same  as  the  distance  between  the  dividers,  5  ft.,  there  is 
plenty  of  room. 


X 

CARS 
Types  of  Cars — Car  Dumps — Cars  for  Special  Purposes — Accessories 

TYPES  OF  CARS 

Doe  Run  Mine  Car. — The  car  used  in  the  mines  of  the  Doe  Run  Lead 
Co.,  in  southeastern  Missouri,  is  of  the  type  requiring  dumping  by  a  tipple. 
Under  many  conditions  this  is  not  much  of  a  drawback,  and  such  cars, 
in  which  the  body  and  wheels  are  tied  tight  together,  are  much  cheaper 
to  keep  in  repair  than  are  those  pivoted  to  a  wheel  truck  so  as  to  allow 
dumping  at  any  place.  Moreover,  they  are  cheaper  in  first  cost.  In 
order  to  permit  placing  the  wheels  under  the  body  they  are  fastened  by 
their  axles  to  two  8-in.,  23-lb.  I-beams  riveted  to  the  bottom  of  the  body, 
which  is  of  %-in.  plate,  Fig.  329.  The  sides  of  J4~m-  plate  are  riveted 
to  this  bottom  plate  without  any  reinforcement  at  the  lap.  The  top  of 
the  car  is  reinforced  by  a  3  X  Ji-in.  strap,  while  4  X  M~m-  pieces  are 
put  on  the  inside  of  the  ends  of  the  car  to  strengthen  them  and  to  dis- 
tribute the  strains  that  come  from  the  draw  rings  over  a  larger  area  of 
the  end  plates.  These  draw  rings  are  used  for  making  up  trains  and  for 
mule  haulage.  The  wheel  base  is  18  in.  and  the  wheels  are  fitted  with 
Whitney  roller  bearings.  A  peculiarity  of  the  body  is  that  it  is  nearly 
square. 

Round-bottom  Car. — In  Fig.  330  are  shown  the  details  of  the  mine 
car  used  by  the  St.  Louis  Smelting  &  Refining  Co.  in  southeastern  Mis- 
souri. The  car  is  made  to  dump  by  a  tipple  arrangement.  It  has  a 
semicylindrical  bottom,  to  which  the  cast-iron  bearings  are  bolted,  no 
truck  being  used.  The  body  is  made  by  riveting  together  plates  J£  in. 
thick.  There  are  five  of  these  plates;  the  bottom  plate  B',  the  two  side 
plates  B,  and  the  two  end  plates  A.  The  side  plates  and  the  semicylin- 
drical bottom  plates  are  lap-jointed,  while  the  end  plates  are  riveted  with 
their  flanges  inside  the  side  and  bottom  plates.  These  end  plates  are 
flanged  at  the  boiler  works  where  they  are  cut,  but  the  rest  of  the  building 
of  the  body  is  done  at  the  company's  shops.  If  desired,  the  plates  could 
be  joined  together  by  angle  irons  which  would  stiffen  the  car  somewhat 
more  than  the  manner  shown.  Around  the  top  of  the  car  there  is  a 
stiffening  band  of  Y±  X  2^-in.  iron. 

413 


414 


DETAILS  OF  PRACTICAL  MINING 


These  cars  have  a  capacity  of  approximately  20  cu.  ft.  and  hold  about 
1  ton  of  lead  ore,  the  gangue  of  which  is  a  magnesian  limestone.  They 
are  made  to  be  trammed  by  hand  or  pulled  in  trains  either  by  mule  or  by 
electric  motor.  On  that  account  hooking  rings  C  are  provided  at  each 
end.  These  are  U-bolts  of  %-in.  iron,  put  through  the  body,  with  stiffen- 
ing plates  of  34-in.  iron  18  in.  square  put  on  the  latest  cars  to  spread  the 
strain  of  the  pull  over  a  larger  portion  of  the  front.  These  U-bolts,  or 


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FIG.    329. SMALL,    RIGID    CAR    WITH    SQUARE-SECTION   BODY. 

hooking  rings,  are  made  with  collars  welded  on,  so  that  they  can  be  riveted 
tight  to  the  body  of  the  car.  Cast-iron  bumpers  D  are  riveted  to  the 
body  at  its  bottom,  where  the  strain  of  the  bump  will  be  distributed  di- 
rectly to  the  reinforcement  afforded  to  the  ends  by  the  riveting  flanges. 
The  bearings  E  for  the  wheels  are  connected  direct  to  the  body  of  the 
car  by  brackets.  These  bearings  are  of  the  Anaconda  type,  the  wheels 
being  mounted  tight  and  the  axles  cut  in  two  at  the  middle.  The  axles 


CARS 


415 


are  held  in  by  the  forks  F.  The  opening  in  the  journal  is  closed  by  a  plate 
fastened  by  four  cap  screws.  A  hole  is  cut  in  it  for  shooting  in  the  oil 
with  a  squirt  gun,  such  as  is  used  in  watering  holes  in  stopes,  the  intention 
being,  however,  since  the  oil  works  through  the  bearing  rather  rapidly, 
to  use  grease  in  the  future. 

Heavy  End-dump  Car  (By  H.  L.  Botsford). — Fig.  331  shows  a  tram 
car  for  underground  use.  It  is  used  in  connection  with  motor  tramming, 
although  it  is  equally  well  adapted  to  hand  work.  The  car  is  constructed 
with  false  bottom,  or  lining  plate,  which  is  removable,  and  which  can 
be  changed  end  for  end  when  the  front  end  of  the  plate  is  worn  out.  The 


PIG.    330. RIGID    CAR    WITH    ROUND   BOTTOM    AND    ANACONDA    AXLES. 

truck  is  of  wood  and  can  be  readily  constructed  by  a  mine  carpenter  and 
blacksmith. 

Copper  Range  Car  (By  Claude  T.  Rice). — The  ore  car  used  at  the 
Baltic,  Trimountain,  and  Champion  mines,  is  in  many  respects  the  best 
mine  car  in  the  Lake  Superior  copper  district.  The  body  of  the  car, 
Fig.  332,  is  long  and  low  so  that  shoveling  into  it  is  easy,  and  as  the  front 
end  is  open  and  the  back  end  somewhat  lower  than  the  sides,  it  is  much 
easier  to  fill  it  than  some  of  the  better  known  types  of  cars.  Its  capacity 
is  2j/£  tons  of  the  Lake  Superior  ore,  which  when  broken  measures  20  cu. 
ft.  per  ton.  In  spite  of  the  length  of  the  car  the  wheel  base  is  short,  while 
the  track  gage  is  only  24  in.  These  dimensions  are  unique  in  the  practice 
of  the  Lake  Superior  copper  region.  The  wheels  are  rigidly  attached  to 


416 


DETAILS  OF  PRACTICAL  MINING 


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TOP  VIEW 
H 

CARS 


417 


the  truck  and  the  weight  is  evenly  distributed  upon  the  wheels  so  that 
the  car  runs  easily.  Bearings  of  the  Peteler  type,  a  modification  of  the 
regulation  railroad  bearings  in  which  the  journal  rotates  in  brasses  are 
used  without  waste  in  the  oil  well.  The  oil  receptacle  may  be  drawn  out 
of  the  solid  bearing  casting  for  filling.  To  prevent  trouble  from  breakage 
of  the  bearing  castings,  they  are  made  of  malleable  iron.  The  bearings 
are  carried  on  overhanging  extensions  of  the  axle.  Because  of  this  the 
axles  must  be  made  strong. 

Stiffening  plates,  which  also  serve  as  wings  by  which  the  car  is  grasped 
when  being  handled  on  the  turntables,  are  used  on  the  corners  of  the  body. 
As  turntables  are  provided  at  all  the  shaft  stations  the  cars  can  always 
be  run  to  the  breast  with  the  front  end  forward  and  the  men  can  shovel 


uc... 


Detail  of  Peteler  Bearing 


Detail  of  WheelsandAxle 


Side  Elevation  Front  Elevation 

FIG.    332. — LONG,    LOW   CAR   WITH   SHORT   WHEEL  BASE. 

into  them  easily.  Leaving  the  front  end  open  requires  the  building  of  a 
rough  wall  of  boulders  across  the  front,  called  by  the  Cornish  miners  a 
"stilling,"  to  hold  back  the  fine  ore,  but  making  it  does  not  take  much 
time.  Doors  were  tried  on  the  cars,  but  it  was  found  that  the  mainte- 
nance was  heavy.  Because  of  the  open  end,  it  is  possible  to  up-end  the 
cars,  put  a  brace  under  the  bodies  and  roll  any  boulders  into  the  front 
end  of  the  car. 

The  truck  was  formerly  made  of  hardwood,  but  that  material  rots 
quickly  underground,  and  the  truck  is  now  made  of  fir,  giving  a  much 
longer  life.  Practically  the  only  maintenance  on  these  cars  is  the  replac- 
ing of  the  trucks.  Owing  to  the  type  of  axle,  the  gage  of  the  track,  the 
short  wheel  base  and  the  even  distribution  of  the  load  on  the  wheels,  as 
well  as  the  excellence  of  the  lubrication,  the  tracks  on  the  levels  may  be 

27 


418 


DETAILS  OF  PRACTICAL  MINING 


laid  at  a  grade  of  3  in.  per  100  ft.  The  tramming  is  generally  done  by 
men  in  pairs.  Because  of  the  length  of  the  car  it  is  not  adapted  to  crooked 
drifts,  although  it  goes  around  curves  without  much  binding. 

Desloge  Car. — The  mine  car  used  by  the  Desloge  Consolidated  Lead 
Co.,  in  southeastern  Missouri,  is  shown  in  the  accompanying  illustration. 
The  car  is  of  the  long,  low  type,  which  has  found  favor  in  the  Lake  copper 
and  iron  districts,  due  to  the  ease  and  rapidity  of  loading.  The  Desloge 
car  stands  33  in.  above  the  rail,  is  5  ft.  long,  44  in.  wide  and  has  a  wheel 
base  of  24  in.  The  body  of  the  car  is  made  up  of  %-m.  plates.  It  has 
been  found  that  by  using  a  car  composed  of  several  plates,  as  seen  in  Fig. 
333,  wrecked  cars  are  more  easily  repaired  than  when  fewer  and  larger 
members  are  employed.  All  the  plates  are  cut  to  the  correct  size  at  the 


FIQ.  333. LOW,  RIGID  CAR  WITH  SPECIAL  AXLES. 

mill,  and  are  assembled  and  riveted  at  the  mine,  %-in.  rivets,  spaced  6  in. 
center  to  center,  and  ^  X  3  X  3-in.  angles  being  used. 

The  2-in.  square  axles  have  collars  immediately  behind  the  wheels, 
which  prevent  any  side  play.  An  umlsual  feature  of  the  car  is  that  these 
axles  can  move  up  and  down  in  iron-lined  notches  cut  in  the  truck  timbers, 
2  in.  wide  and  3  in.  deep.  This  enables  the  wheels  to  follow  any  vertical 
inequalities  of  the  track.  In  order  to  make  the  car  itself  ride  more  easily, 
coil  springs  are  fitted  in  the  notches  between  the  axles  and  the  truck 
timbers.  The  longitudinal  truck'  timbers  project  3  in.  at  both  ends  and 
act  as  bumpers.  The  car  body  being  fastened  rigidly  to  the  trucks, 
tipples  are  used  in  dumping;  the  cars  have  squirrel-cage  doors  which  per- 
mit the  use  of  the  spear  tipple.  The  link-and-two-clevis  coupling  arrange- 


CARS 


419 


ment  is  generally  used.  In  order  to  prevent  pins  from  being  lost,  the 
upper  hole  of  the  clevis  is  made  smaller  than  the  lower  one,  the  pin  is  put 
through  the  upper  hole  and  upset  just  enough  to  prevent  it  from  being 
pulled  back,  while  being  still  small  enough  to  go  through  the  lower  hole 
easily. 

Two  Sublevel  Cars  (By  H.  L.  Botsford). — In  the  sublevel  system  of 
mining  on  the  iron  ranges  there  is  need  for  a  special  tram  car  which  can 
be  easily  brought  into  and  removed  from  the  subdrifts.  The  only  access 
to  the  subdrifts  is  usually  by  a  raise  or  winze  through  which  it  is  impossible 
or  inconvenient  to  take  the  main-level  cars. 

Figs.  334  and  335  show  two  types  of  small  tram  cars  which  are  well 
adapted  to  this  work.  They  are  so  constructed  as  to  be  readily  disman- 
tled for  moving  and  quickly  assembled  again.  A  light  steel  car  is  shown 


Truck  hinged 
here 


Up //'---Hll 

X  _,/        1 


k- -^'-- 

FIG.  334. STEEL  SUBLEVEL  CAR. 


20"' 

FIG.    335. WOODEN    SUBLEVEL    CAR. 


in  Fig.  334.  The  sides  are  bolted  to  the  bottom  and  the  end  to  the  bottom 
and  sides.  The  front  axle  only  is  bolted  to  the  car  box.  The  front  and 
rear  axles  are  connected  by  straps,  so  that  the  box  lifts  off  the  rear  axle 
when  being  dumped.  A  wooden  car,  built  with  detachable  sides  and  end, 
is  shown  in  Fig.  335.  The  truck  is  hinged,  and  only  the  front  half  is 
fastened  to  the  car  box.  The  sides  of  the  car  are  provided  with  cleats 
which  fit  into  stirrups  bolted  to  the  bottom  planking. 

Pickands-Mather  Sublevel  Car. — The  accompanying  drawing,  Fig. 
336,  represents  the  standard  car  designed  for  sublevel  work  in  the 
Pickands,  Mather  &  Co.  properties  on  the  Mesabi  range.  The  nature  of 
the  work  is  such  that  cars  must  be  of  a  size  to  permit  easy  handling  in 
narrow,  crushed  drifts  and  around  sharp  curves.  The  car  shown  has  a 
capacity  of  20  cu.  ft.  which  is  equivalent  to  about  a  ton  of  loose  ore.  This 


420 


DETAILS  OF  PRACTICAL  MINING 


is  an  advantage  in  keeping  a  record  of  the  work  performed  by  various 
gangs.  The  truck  is  made  strong  to  withstand  rough  usage  and  the  body 
can  be  easily  straightened  if  accidentally  dropped  down  a  chute.  The 
tipping  device  is  placed  near  the  center  of  the  car,  which  makes  it  easy 
to  dump.  The  length  of  the  car,  5  ft.,  in  proportion  to  its  wheel  base, 
is  a  noteworthy  feature.  It  is  also  comparatively  low,  for  its  breadth  and 
length,  which  renders  shoveling  easier.  The  car  will  dump  only  toward 
the  front.  The  12-in.  wheels  turn  on  the  axles.  The  axles  are  rigidly 
attached  to  the  sills,  which  are  made  of  channels  and  braced  by  plates 
over  the  top  and  on  one  end. 

Federal  Gable -bottom  Car. — Fig.  337  shows  the  details  of  the  gable- 
bottom  car  used  on  the  electric  haulageways  at  the  No.  1  shaft  of  the 
Federal  Lead  Co.  in  southeastern  Missouri.  This  car  has  a  capacity  of 
28  cu.  ft.  The  locking  mechanism  is  worthy  of  mention,  as  it  is  rapid  and 
easy  to  operate.  It  consists  of  the  shaft  F  to  which  the  double  lever  D  and 


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U 2^~»W^/5^-" 


U-  ......  29i'-'—    --- 

FIG.    336.  —  FRONT   DUMPING   CAR   USED   FOR   SUBLEVEL   WORK. 

the  operating  lever  A  are  keyed.  To  the  ends  of  the  double  lever  D  are 
pinned  the  door  levers  B  and  C,  which  are  bent  to  let  their  pin  connections 
with  lever  D  come  into  dead-center  positions  with  respect  to  the  pins  E  when 
the  doors  are  shut,  thus  locking  the  doors.  The  outer  ends  of  each  of  the 
door  levers  B  and  C  go  over  the  pins  E,  which  are  bolted  to  the  doors  of 
the  car.  Each  end  of  the  car  is  fitted  with  the  locking  mechanism,  but  as 
levers  D  of  both  ends  are  keyed  to  the  same  shaft  F,  the  unlocking  of  one 
end  of  the  car  also  unlocks  the  other  end.  The  bar  used  in  removing  any 
boulders  that  hang  up  in  the  car  may  be  used  to  trip  the  locking  mechan- 
ism by  catching  the  link-bolt  of  one  of  the  locking  arms  and  giving  it  an 
upward  lift.  This  is  more  convenient  and  easier  than  the  use  of  the 
locking  lever  A  for  opening  and  closing  the  doors.  In  fact,  the  lever  A 
may  be  entirely  omitted  if  desired.  The  locking  mechanism  is  made  of 
cast  steel. 

Double-truck  Gable-bottom  Car.  —  Fig.  338  illustrates  a.  car  designed 
for  use  on  the  stockpile  trestle  of  the  Kennedy  mine  on  the  north  Cuyuna 


CARS 


421 


iron  range.  The  car  will  hold  100  cu.  ft.,  or  about  6  tons  of  ore.  The 
electric  locomotive  in  use  on  the  trestle  will  handle  one  car  per  trip.  The 
body  of  the  car  is  hopper-shaped  with  a  gable  through  the  center  and  two 


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FIG.    337.  -  DETAILS    OP    FEDERAL   LEAD    CO.  S    GABLE-BOTTOM    MINE    CAR. 


side  doors  swinging  out  and  up.  The  ends  of  the  hopper  are  pitched  at 
60°  and  the  gable  is  about  50°,  these  steep  pitches  being  necessary  from 
the  fact  that  the  ore  is  sticky  and  hangs  to  a  flat  slope.  It  is  possible  also 


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CROSS-SECTION  A-A 


PIG.    338.  -  RAPID-DUMPING    6-TON    CAR    FOR   STOCKPILE    TRESTLE. 

that  in  the  coldest  weather  the  ore  may  freeze  slightly,  which  would  cause 
it  to  stick  to  the  car.  The  inside  of  the  body  is  protected  with  a  2-in. 
lining  of  wood.  The  two  side  gates  give  an  extremely  fast  discharge, 
since  they  provide  about  a  maximum  opening  for  the  passage  of  the  ore. 


422 


DETAILS  OF  PRACTICAL  MINING 


It  is  extremely  important  that  the  cars  dump  quickly,  as  it  will  tax  the 
capacity  of  the  system  to  handle  the  ore  as  fast  as  it  is  hoisted  at  best,  the 
trestle  being  unusually  long  considering  the  size  of  the  mine.  The  double 
trucks  make  it  possible  to  swing  the  entire  body  in  between  and  thus  keep 
it  lower  and  more  stable.  The  company  itself  manufactures  everything 
but  the  trucks. 

Middle-dump  Mine  Car  (By  W.  W.  Shelby). — The  2-ton  middle-dump 
mine  car,  shown  in  Fig.  339,  has  been  in  service  for  years  at  the  Smuggler- 
Union  mine.  The  sides  and  bottom  are  J^-in.  iron  and  are  held  together 
by  2  X  2  X  %-in.  angle  irons.  A  1J^  X  J^-in.  strap  is  riveted  around 
the  top  of  the  car.  The  chain  across  the  top  at  the  middle  prevents  de- 
formation and  makes  the  pivots,  about  which  the  car  dumps,  more  rigid. 
Three-inch  planks  are  used  for  lining  the  bottom  and  for  bumpers,  the  rest 
of  the  car  being  entirely  of  iron.  In  order  to  dump  the  car,  lever  A  is 


PIG.    339. SMUGGLER-UNION    CAB   THAT  BREAKS   IN   THE    MIDDLE. 

knocked  to  one  side  and  latch  B  forced  upward  by  a  light  blow  from  a  pick 
or  a  single  jack;  the  car  will  then  break  in  the  middle,  dropping  the  ore  into 
pockets  or  bins  beneath  the  track.  The  trucks  are  so  spaced  that  the  load 
between  them  is  only  a  little  greater  than  that  in  the  ends,  thus  avoiding 
undue  strain  upon  the  latch  and  its  safety  lever.  The  truck  has  fixed 
wheels  and  is  unusual  in  that  there  is  no  bottom  half  of  the  journal,  the 
lower  half  of  the  axle  being  exposed.  A  U-bolt  extending  beneath  the 
axle  holds  the  wheels  to  the  truck  when  the  car  is  lifted  from  the  track. 
Those  cars  that  come  to  the  surface  are  automatically  oiled  by  passing 
over  two  rollers  of  such  dimensions  and  so  placed  between  the  rails,  that 
the  lower  parts  of  the  axles  beneath  the  bearings  touch  them  in  passing. 
These  wooden  oiling  rollers  are  free  to  revolve;  a  sack  or  cloth  is  tacked  on 
their  circumferences,  and  being  suspended  in  a  tank  of  oil,  they  are  them- 
selves automatically  oiled  and  furnish  a  good  lubricating  surface  to  the 
axles.  The  cars  are  coupled  by  chains. 


CARS 


423 


Red  Jacket  Car. — The  car  shown  in  Fig.  340  is  used  at  the  Red  Jacket 
shaft  of  the  Calumet  &  Hecla  company  in  the  copper  district  of  Michigan. 
The  most  interesting  feature  of  the  car  is  the  manner  of  reinforcing  the. 
bottom.  Two  plates  are  used,  bolted  together  to  form  a  beam,  with  a 
filling  of  wood  to  give  stiffness.  The  top  plate  is  %  in.  thick  while  the 
bottom  plate  is  ^  in.  thick,  with  wood  filling  2  in.  thick  at  the  center. 
The  gage  of  the  track  is  48  in.  and  the  car  has  a  capacity  of  2%  tons  of 
conglomerate  ore.  This  car,  owing  to  the  construction  of  the  bottom, 
carries  the  load  without  strain,  although  the  wheels  are  carried  by  trun- 
nions fastened  to  the  sides  of  the  car  instead  of  by  axles  extending  clear 


FIG.    340. CALUMET    &    HECLA    CAR   WITH   WHEELS    ON   TRUNNIONS. 


under  the  body.  This  is  partly  because  of  the  limits  on  size  imposed  by 
the  size  of  the  cages  in  the  Red  Jacket  shaft,  and  partly  because  the  body 
of  the  car  had  to  be  kept  as  low  as  possible,  for  use  with  rope  haulage. 
Axles  could  not  be  used  and  have  the  cars  at  the  desired  capacity.  The 
car  is  fitted  with  doors  at  each  end  to  aid  in  loading  boulders  from  the 
floors  of  the  drifts  when  cutting-out  stoping  is  being  done,  although  most 
of  the  ore  after  stoping  proper  begins  is  loaded  from  chutes.  As  the  car 
is  used  on  the  rope  haulage  levels,  buffers  are  provided  at  the  corners. 
The  car  is  dumped  by  a  chain  coming  down  from  an  air  cylinder  over  the 
measuring  pockets  at  the  shaft.  These  cars  stand  up  to  the  work  well  and 
no  trouble  comes  from  bowing  of  the  bottom.  The  same  design  of  bottom 
is  used  for  the  7^-ton  cars  serving  the  underground  bins  at  Osceola  No. 


424 


DETAILS  OF  PRACTICAL  MINING 


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CARS 


425 


13  shaft;  here  the  track  has  a  gage  of  5  ft.  9  in.  in  order  to  keep  the  car 
low  and  short  for  dumping. 

End-dumping  Stockpile  Car  of  Wood  (By  E.  W.  R.  Butcher). — Fig. 
341  shows  a  stockpile  car  of  the  front-dump,  turntable  type,  used  by  the 
Kepublic  Iron  &  Steel  Co.  at  some  of  its  mines  on  the  Mesabi  range.  The 
size  of  the  car  varies  with  the  size  of  skip  used.  It  is  handled  by  an  electric 
motor  to  which  it  is  attached  with  an  iron  bar  1J/2  X  4  in.  by  8  ft.  This 
bar  acts  as  a  protection  to  the  motor  when  the  car  goes  over  the  end  of  the 
stockpile.  The  car  is  built  largely  of  wood;  all  of  this  is  oak,  which,  al- 
though much  more  expensive  than  pine,  needs  less  repair  and  is  cheaper  in 
the  end.  The  bottom  of  the  car  is  lined  with  a  J^-in.  iron  plate.  Form- 
erly the  bottom  lining  consisted  of  1-in.  plank,  but  this  had  to  be  replaced 
too  frequently.  The  release  handle,  operating  in  about  the  usual  manner, 
allows  the  car  to  dump  on  its  hinge  and  opens  the  door  at  the  same  time. 
Should  the  car  not  dump  of  itself,  a  wooden  lever  arm  is  placed  in  the 


€-10" 


— 2-0 > 

PIG.    342. WOODEN,    END-DUMPING    TURNTABLE    CAR. 

dump  socket  on  the  side  and  the  car  raised  until  it  does  dump.  The 
4  X  8-in.  timbers  on  either  side  of  the  hinge  act  simply  to  steady  the  car. 
The  king  bolt  for  the  turntable  is  not  fastened  to  the  truck;  this  allows 
it  to  pull  out  and  release  the  body  of  the  car  from  the  truck  when  it  goes 
over  the  edge  of  the  stockpile.  It  has  been  found  less  trouble  to  get  back 
the  body  of  the  car  after  it  has  gone  entirely  over  the  pile,  than  to  get  the 
truck  and  car  back  when  they  are  hanging  on  the  edge.  To  release  the 
car  for  swinging,  arm  A  is  raised;  until  it  is  thus  raised,  a  1  X  1%-in. 
extension  at  its  bottom,  fitting  under  a  block,  prevents  the  car  from  rising, 
while  this  same  extension,  together  with  the  vertical  portion  of  the  arm, 
is  held  so  as  to  prevent  any  side  motion.  When  the  car  is  swung  back 
again  to  normal  position,  the  arm  falls  by  itself  into  its  place.  The  four 
corner  bolts  which  hold  the  bottom  plate  B  to  the  bed,  also  hold  the 
journal  boxes,  thus  eliminating  four  bolts.  The  5-in.  iron  washer  on  this 
plate  gives  a  smaller  friction  resistance  to  turning  and  can  be  easily  re- 
placed when  worn. 

Surface  Tram  Car. — Fig.  342  shows  a  not  uncommon  type  of  tram  car 


426 


DETAILS  OF  PRACTICAL  MINING 


around  the  iron  ranges  for  use  on  the  surface  to  handle  skip-hoisted 
material.  It  is  of  the  end-dump,  turntable  type  and  is  constructed 
chiefly  of  wood;  it  is  rather  lower  than  those  frequently  used.  The 
socket  at  the  rear  end  is  for  the  insertion  of  the  dumping  bar.  The 
manner  of  suspending  the  door  some  distance  above  the  top  of  the  car 
is  noteworthy. 

CAR  DUMPS 

Rack-and-pinion  Front-rotating  Dump. — In  Fig.  343  are  shown  the 
details  of  construction  of  the  dump  or  tipple  used  at  the  mines  of  the  St. 
Louis  Smelting  &  Refining  Co.  in  southeastern  Missouri,  for  dumping 
cars  made  with  the  truck  fastened  rigidly  to  the  body.  In  this  tipple 
the  cradle  proper  carrying  the  car  wheels  rides  ahead  on  a  framework 


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FIG.    343. CRADLE    DUMP    OF    ST.    LOUIS    SMELTING    &    REFINING    CO. 

before  it  dumps  the  car.  The  frame  pieces  on  which  the  cradle  travels 
end  in  hooks  or  horns  that  catch  the  cradle  and  keep  the  car  from  going 
clear  over;  consequently,  no  reliance  has  to  be  placed  upon  a  chain  fast- 
ened to  a  crossbar  of  the  cradle  and  anchored  to  a  tie  of  the  track  or 
fastened  in  some  other  way  to  solid  ground.  This  type  of  dump  is  some- 
what more  expensive  than  the  type  in  which  the  cradle  swings  on  its 
axle  and  does  not  travel  forward. 

The  frame  on  which  the  cradle  travels  is  made  up  of  two  castings 
bolted  to  timbers  running  out  across  the  chute  into  which  the  ore  is  to 
be  dumped.  The  castings,  as  stated,  have  horns  that  come  up  and  hook 
over  the  wheels  of  the  cradle  and  since  the  cradle  wheels  have  teeth  which 


CARS  427 

mesh  with  teeth  on  the  frame  castings,  the  cradle  can  turn  up  only  a 
certain  distance.  These  teeth  do  not  carry  the  weight  of  the  cradle,  for 
the  casting  extends  up  to  form  a  track  ledge  slightly  higher  than  the  tops 
of  the  teeth  on  which  the  wheels  of  the  cradle  roll.  The  function  of  the 
teeth  is  only  to  regulate  the  forward  motion  of  the  cradle  wheels  and  keep 
them  even -as  well  as  to  limit  the  end  of  the  dump  when  the  wheels  strike 
the  hooks  of  the  frame  pieces.  The  cradle  dump  wheels  A  are  fastened 
to  the  cradle  frame  by  bolts  that  pass  through  slots  in  the  crossarms  of 
the  wheels.  In  this  way  it  is  possible  to  level  the  cradle  frame  with 
respect  to  the  dump  wheels.  The  cradle  frame  is  composed  of  the  two 
cross-braces  B  to  which  the  dump  wheels  are  bolted  and  to  which  the  track 
straps,  and  the  loops  C,  for  catching  the  car  wheels,  are  riveted.  A  center 
strap  D  is  fastened  to  the  bridle  strap  E,  which  extends  forward  to  catch 
the  front  of  the  car  and  take  part  of  the  strain  that  would  otherwise 
come  down  to  the  loops  C,  while  the  car  is  dumping.  In  case  the  cars  will 
not  right  themselves  after  they  have  dumped,  it  is  customary  to  fasten 
weights  to  the  back  cross-strap  B.  The  track  straps  C,  of  course,  extend 
back  farther  than  the  rest  of  the  dump  so  as  to  join  with  the  rails  of  the 
track  leading  up  to  the  tipple.  When  the  car  has  righted  itself  and  the 
cradle  has  run  back  to  its  proper  position  on  the  frame,  these  drop  down 
upon  a  crosspiece  of  iron  so  that  they  come  just  level  with  the  tops  of  the 
rails  of  the  approach. 

The  dump  illustrated  is  designed  for  a  1-ton  car  of  the  usual  type 
used  in  hand  tramming  at  mines.  The  drawing  gives  the  manner  of 
proportioning  the  different  members  of  the  cradle  and  frame  so  that  they 
will  stand  up  to  the  strain  of  the  work,  but  the  dimensions  of  the  cradle 
have  to  be  changed,  of  course,  to  suit  the  dimensions  of  the  individual 
car  that  they  are  to  serve.  The  dump  is  made  of  cast  steel;  it  has  beerr 
in  use  for  several  years  and  works  satisfactorily.  Some  trouble  has  been 
experienced  owing  to  the  occasional  breaking  of  a  hook  leg  when  a  car 
has  been  run  into  the  dump  with  more  than  ordinary  force. 

Simple  Cradle  Dump  (By  Claude  T.  Rice). — In  the  accompanying 
illustration,  Fig.  344,  are  shown  the  details  of  the  car  dump  used  at  the 
Doe  Run,  the  St.  Joseph,  the  Federal  and  some  of  the  other  mines  in  the 
Flat  River  district  of  Missouri,  where  the  ore  is  hoisted  to  the  surface  in 
cars.  This  tipple  is  made  entirely  of  iron,  and  as  shown  in  the  drawing, 
is  designed  for  dumping  a  1-ton  car.  The  iron  bars  that  serve  as  rails 
run  back  to  a  sole  plate  under  the  track  rails  leading  up  to  the  dump  so 
that  the  bars  will  come  flush  with  the  tops  of  the  rails.  The  other  ends 
of  these  bars  are  bent  and  brought  back  far  enough  to  come  over  the 
tops  of  the  back  wheels  when  the  car  has  been  run  forward  on  the  dump. 
To  strengthen  these  loops  they  are  tied  to  the  lower  part  of  the  cradle  by 
two  straps,  offset  to  the  outside.  The  dump  is  so  proportioned  that  the 


428 


DETAILS  OF  PRACTICAL  MINING 


center  of  gravity  of  the  loaded  car  will  be  slightly  ahead  of  the  rotating 
shaft  of  the  dump,  when  the  car  wheels  are  engaged  by  the  loops,  yet  not 
far  enough  ahead  but  that,  after  the  ore  has  run  out,  the  weight  of  the 
back  rails  of  the  dump  will  be  enough  to  put  the  car  and  tipple  back  into 
a  horizontal  position.  Consequently  the  proportions  have  to  be  made 
according  to  the  dimensions  of  the  cars  used;  the  drawing  shows  only  the 
general  design  of  a  style  of  tipple  that  has  given  excellent  service  after 
years  of  use.  To  prevent  the  tipple  or  dump  from  turning  so  far  that  it 
cannot  right  itself,  a  chain  is  tied  to  the  back  and  is  fastened  to  the  floor 
above  the  bin  into  which  the  ore  is  being  dumped. 


Bearing  Stand 
FIG.    344. TYPICAL   DUMPING    CRADLE    USED    IN    SOUTHEASTERN    MISSOURI. 

Tipple  for  Seven-car  Train  (By  J.  R.  McFarland). — At  the  Cactus 
mine  of  the  South  Utah  Mines  &  Smelters,  a  dump  was  operated  which 
unloaded  seven  4-ton  cars  at  a  time.  The  dump  consisted  of  a  steel 
cylindrical  framework  of  a  length  equal  to  seven  cars,  which  rested  on  four 
pairs  of  rollers,  as  shown  in  Fig.  345.  Rails  on  which  the  cars  ran  in  were 
laid  in  the  bottom.  Two  angle  irons  extended  the  full  length  on  the  in- 
side of  the  top  in  such  a  position  as  to  embrace  the  tops  of  the  cars,  as 
can  be  seen  in  the  illustration.  An  air-driven  engine  placed  opposite 
the  side  of  the  cylinder,  drove  a  drum  carrying  a  wire  rope  which  was  also 
wrapped  around  the  cylinder.  The  motor  brought  a  train  of  14  cars 


CARS 


429 


from  the  mine  and  backed  seven  cars  into  the  dump,  the  engine  was 
started  and  the  cylinder  rolled  over  to  the  position  shown  in  the  lower 
drawing,  with  the  inverted  cars  resting  on  the  angle  irons  inside  the  frame. 
It  was  then  rolled  back,  righting  the  cars,  which  were  run  out  by  the  motor, 
and  the  other  seven  cars  run  in  and  dumped.  This  arrangement,  which 
proved  itself  a  valuable  timesaver,  was  built  by  Silver  Bros.,  Salt  Lake 
City,  Utah. 

I  4x4" Angle 


AirCylmder 


••-  44-2  - 

DUMPING  CYLINDER 
Drum 


FIG.    345. CYLINDER   FOR   DUMPING    A   TRAIN   OF   SEVEN   CARS. 

A 

Tipple  for  3-ton  Car. — The  complete  turnover  tipple,  shown  in  Fig. 
346,  was  designed  to  unload  the  3-ton  end-closed  cars  used  in  the  magne- 
tite mines  at  Mineville,  N.  Y.  The  position  of  the  tipple  axles  depends 
upon  the  style  of  car  to  be  dumped.  The  train  of  cars  is  uncoupled  some 
distance  from  the  tipple  and  dropped  by  gravity  to  the  tipple,  where  they 
turn  through  an  angle  of  almost  180°  to  dump.  The  cars  are  righted  by 
applying  pressure  to  the  hand  brake,  until  the  projecting  rails  rest  on  the 


<=f 


FRONT   ELEVATION 


SIDE     ELEVATION 


FIG.    346. AUTOMATIC   TIPPLE    FOR    MINEVILLE    CARS. 

8  X  8-in.  rail  block.  The  cars  after  dumping  are  started  from  the  tipple 
by  hand  and  the  grade  from  the  tipple  takes  the  cars  to  the  "empty" 
spur  by  gravity. 

Spear-type  Dump. — In  Fig.  347  are  shown  the  details  of  the  construc- 
tion of  the  spear  type  of  car  dump  which  is  used  in  many  coal  mines, 
but  which  is  not  so  frequently  seen  at  metal  mines.  It  is  used,  however, 
by  the  Desloge  Consolidated  Lead  Co.  in  southeastern  Missouri.  This 


430 


DETAILS  OF  PRACTICAL  MINING 


type  of  dump  has  its  advantage,  especially  when  low,  long  cars  are  used. 
Any  car  that  is  to  be  dumped  with  a  spear  type  of  tipple  must  be  fitted 
with  a  squirrel-cage  type  door,  and  this  door  must  have  a  loop  extending 
above  it  for  catching  on  the  spear,  so  that  it  will  be  raised  in  respect  to  the 
body  of  the  car  as  the  tipple  dumps  the  load.  The  long  car  body  has  a 
good  deal  of  side  movement  from  variations  in  the  way  that  the  car  is 
seized  with  respect  to  the  rails;  therefore  the  loop  for  the  spear  should  be 
at  least  10  in.  wide,  and  8  in.  high. 

In  the  spear  type  of  tipple  the  car  body  is  dropped  enough  by  the 
cradle  so  that  the  bottom  of  the  car  assumes  an  angle  greater  than  the 
angle  of  repose  of  the  material.  The  front  of  the  body  then  strikes  a 


Bearing  Stra 


4*$     ^.—.24".~..y^2" Diameter 

§ide  View  of  Tipple 
FIG.    347. DESLOGE   DUMP    AND    ARRANGEMENTS    OF    SPEAR. 

crosspiece  or  the  floor,  so  that  it  cannot  tip  farther.  In  rigging  up  a 
dump  at  a  chute  where  the  roof  is  so  high  that  the  spear  cannot  be  sus- 
pended from  it,  two  uprights  are  carried  up  from  the  stringers  which  sup- 
port the  cradle  bearings.  These  uprights  are  fastened  by  a  single  bolt  in 
each  side;  on  these  two  bolts  the  uprights  can  turn  as  on  pivots.  Angle 
braces,  also  fastened  by  a  single  bolt  at  each  end,  secure  the  uprights 
from  pushing  forward  when  the  door  strikes  the  spear.  When  blasting 
near-by,  the  bolts  of  the  strap  braces  can  be  taken  out  and  the  whole 
frame  lowered  down  on  the  ground  where  it  will  not  be  damaged  by 
flying  rocks.  The  front-  support  of  the  spear  must  be  arranged  so  that  it 
will  slide  back  on  the  spear  and  lift  up  the  free  end,  as  the  car  comes  for- 


CARS 


431 


ward  into  the  dump.  The  spear,  furthermore,  must  catch  the  loop  on  the 
car  door  a  little  ahead  of  the  tipping  of  the  car,  so  that,  if  for  any  reason 
there  is  a  failure  of  the  spear  to  catch  the  loop,  the  car  will  not  tip  with  the 
door  unlifted,  possibly  causing  trouble  through  overbalancing  of  the  car. 
Sublevel  Car  Dump  (By  L.  D.  Davenport). — Various  kinds  of  tipples 
for  end-dump  cars  have  been  tried  in  the  Chisholm,  Minn.,  mines  at 
different  times.  Most  of  these  required  frequent  repairing,  and  trouble 
was  caused  by  fine  ore  getting  under  the  rockers.  Cars  hinged  so  that 
they  would  dump  without  the  wheels  leaving  the  track  were  also  used  at 
one  time.  One  of  the  objections  to  these  cars  was  the  inconvenience  in 
taking  them  from  one  level  to  another.  At  present  all  sublevel  cars  are 
made  with  the  boxes  fastened  directly  to  the  trucks.  These  cars  are  of 
25-  and  41-cu.  ft.  capacity  with  14-in.  wheels  running  loose  on  the  axles. 


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info   roun  , 

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across  raise 


FIG.    348. SIMPLE    FIXED    DUMPING    ARRANGEMENT. 

Fig.  348  shows  a  typical  car  dump  as  made  at  present.  The  rails  are 
cut  off  18  in.  back  from  the  raise  and  a  collar-piece  of  round  timber  is 
hitched  into  the  ground  at  the  edge  of  the  raise.  A  dumping  bar  is 
placed  4  ft.  6  in.  above  this  collar  and  parallel  to  it.  The  loaded  car  comes 
down  the  track  and  just  before  reaching  the  dump  the  miner  throws  the 
lever  which  unfastens  the  car  door,  the  front  wheels  drop  about  4J£  in., 
the  front  end  of  the  truck  strikes  the  collar-piece  and  the  car  dumps  at  an 
angle  of  about  45°.  The  dumping  bar  prevents  any  chance  of  the  car's 
going  into  the  raise.  This  bar  is  sometimes  made  of  a  short  piece  of  rail. 
Poles  or  short  pieces  of  rail  are  hitched  across  the  raise  to  prevent  anyone 
from  falling  through.  These  poles  are  placed  low  enough  to  allow  plenty 
of  room  for  the  car  door  to  swing  open.  After  the  car  has  dumped,  one  or 
two  miners  grasp  the  handle  at  the  rear  end  and  with  one  pull  the  rear 
wheels  come  down  on  the  track,  the  front  wheels  are  lifted  clear  of  the 


432 


DETAILS  OF  PRACTICAL  MINING 


CARS  433 

ground  and  as  the  car  moves  back  at  the  same  time,  the  front  wheels  also 
come  down  on  the  rail.  This  dumping  arrangement  for  end-dump  cars 
is  simple,  safe,  easily  made  and  requires  little  repairing. 

CARS  FOR  SPECIAL  PURPOSES 

Combined  Transfer  and  Dump  Car. — In  the  accompanying  drawing, 
Fig.  349,  is  shown  the  construction  of  the  transfer  cars  used  at  the  shafts 
of  the  St.  Louis  Smelting  &  Refining  Co.  in  southeastern  Missouri.  The 
ore  is  hoisted  to  the  surface  in  1-ton  cars  on  single-deck  cages,  and  at  the 
surface,  instead  of  tramming  the  ore  cars  to  the  bins  by  hand,  they  are 
put  on  transfer  cars  which  are  equipped  with  motor  drive.  The  method 
has  its  advantages  and  its  disadvantages,  but  the  construction  of  the  trans- 
fer car  is  interesting  as  the  idea  is  applicable  to  transfer  cars  used  for  other 
purposes.  The  frame  A  of  the  car  is  of  cast  steel.  Longitudinal  members 
extend  out  beyond  the  deck  of  the  car  far  enough  to  take  the  bearings  for 
the  wheels.  The  14-hp.  motor  is  mounted  to  drive  the  back  axle,  and 
the  braking  is  done  on  the  wheels  of  that  axle.  The  controller  is  carried 
on  a  raised  platform  resting  on  a  cast-iron  frame  bolted  to  the  main 
frame  of  the  car.  To  the  main  frame  and  running  crosswise  with  it  is 
bolted  the  dump  frame  B.  This  dump  is  of  the  rack-and-pinion  or 
traveling-cradle  type  which  is  especially  good  in  this  class  of  work. 

The  mine  car  is  locked  in  place  by  a  locking  dog  so  that  it  cannot  run 
back  off  the  cradle.  This  is  shoved  in  place  by  the  lander's  foot  when  he 
puts  the  mine  car  on  the  transfer  car.  The  accidental  dumping  of  the 
cradle  is  prevented  by  the  hook  H,  which  is  held  up  in  place  against  the 
cradle  by  the  hook  springs  D,  as  shown  in  the  drawing.  The  hook  is 
keyed  to  the  hook  shaft,  as  is  the  operating  lever  arm  E  by  which  the  hook 
is  pulled  back  off  the  crossbar  of  the  dump  cradle  at  the  proper  time. 
This  lever  controlling  the  dump  is  operated  by  the  motorman's  foot.  The 
lever  F  extending  up  to  the  height  of  the  controller  is  the  brake  lever  which 
is  operated  by  hand,  thus  allowing  the  brake  to  be  put  on  under  closer 
control  than  if  a  foot  brake  were  used.  It  is  by  this  brake  that  the  car  is 
stopped  even  with  the  landing  tracks.  The  brake  link-lever  G,  is  fitted 
with  a  spring  /,  which  holds  the  brake  beam  off  the  wheels.  To  prevent 
the  motorman  from  falling  off  the  car,  a  railing  of  pipe  /  is  carried  around 
the  controller  platform.  A  return  wire  is  used  on  the  trolley  circuit  so 
that  a  double-runner  trolley  pole  is  needed. 

Car-transfer  System  in  Rockhouse.^Figs.  350  to  353  illustrate  a 
rockhouse  used  for  ore  crushing  and  storage.  The  ore  is  hoisted  in 
cars  on  cages  instead  of  in  skips,  and  auxiliary  cars  are  used  to  carry  the 
underground  cars  to  the  grizzlies,  dump  them  and  return  them  to  the 
cage.  Fig.  350  shows  a  plan  and  section  of  the  working  floor,  or  feeding 

28 


434 


DETAILS  OF  PRACTICAL  MINING 


floor  for  the  crushers,  together  with  the  caging  or  transfer  floor  around  the 
shaft.  The  loaded  car  is  pushed  from  the  cage,  trammed  a  few  feet,  and 
loaded,  on  the  transfer  car  shown  in  Fig.  351.  This  is  in  effect  a  movable 
tipple.  It  operates  on  a  track  laid  in  a  pit.  The  underground  car 
mounted  on  this  transfer  car  is  trammed  to  a  point  opposite  the  grizzly, 
dumped  over  the  latter  and  trammed  further  to  a  track  leading  at  right 
angles  past  the  shaft.  Here  it  is  pushed  from  the  tipple  transfer  car  and 
trammed  on  its  own  wheels  to  another  transfer  car,  which  also  operates 


R 


m 


Transfer 

car  r; 

Depth  2-6 


Shaft 


K4'->\ 


Trans  f 
Unloading  floor  for  shaft          Car} 
Transferor.,                                    J,                 ^ 

?/ 
[f 

-  Tipple 

IT 

Snaff- 

^ 

± 

m 

^ 

EN<5.&.niM   _iOU«;r,Au 

'"  '•'Working  Floor 
FIG.    350. LAYOUT    OF    CRUSHER    HOUSE. 


in  a  pit  on  the  other  side  of  the  shaft.  Loaded  on  this,  it  is  trammed  to  a 
track  leading  into  the  shaft  on  the  side  opposite  to  that  from  which  it  was 
unloaded  and  is  then  ready  for  loading  on  the  descending  cage.  Fig. 
352  shows  this  second  transfer  car.  Its  peculiar  design  is  for  the  purpose 
of  taking  care  of  tank  cars,  in  which  water  is  hoisted  from  the  mine,  and 
providing  means  of  emptying  the  water  into  a  discharge  launder.  The 
underground  car  itself  is  shown  in  Fig.  353.  This  method  of  hoisting,  of 
course,  is  far  inferior  to  the  use  of  skips  in  point  of  economy.  Its  use  in 
this  case  seems  to  be  a  survival  of  old  practice. 


CARS 


435 


436 


DETAILS  OF  PRACTICAL  MINING 


Car  for  Tramming  Drill  Steel. — In  the  Joplin  district  the  ore  is 
trammed  almost  entirely  in  buckets.  These  buckets  rest  upon  low,  flat- 
topped  cars  that  are  not  convenient  for  transporting  steel,  dynamite, 
machines  and  other  supplies  about  the  mine.  In  Fig.  354  is  shown  a 
suitable  car  for  such  purposes.  The  body  of  the  car  is  raised  high  enough 
from  the  track  to  be  convenient.  On  top  of  this  is  a  semicircular  rack 


*     2"Plank  Flo?r. 


14  Wheel 
FIG.    352. TRANSFER    WATER    CAR. 


FIG.    353. ORDINARY 

MINE    CAR. 


made  of  2  X  J^-in.  strap  iron.  It  is  strapped  together  longitudinally  only 
at  the  top  so  that  in  tramming  dynamite  to  the  underground  magazine  the 
boxes  can  be  piled  flat  on  the  deck  of  the  body,  which  is  about  12  in.  wide. 
The  other  details  of  the  car  are  evident  from  the  drawing. 

Skip  Car  for  Flat  Grades. — The  details  of  construction  of  a  skip  car 
for  flat  grades  are  shown  in  Fig.  355.     These  cars  are  used  in  the  Joplin 


o 

0 

o 

\-iif 

*!-*• 

^ 

a 

/-v 

FIG.    354. JOPLIN   CAR   FOR   TRAMMING    MINE    SUPPLIES. 

district,  chiefly  for  transferring  the  ore  from  a  subsidiary  shaft  to  the 
mill  hopper  or  bin,  in  some  instances  for  hauling  boulders  up  an  incline 
to  the  dump,  and  in  other  instances  for  conveying  dewatered  tailings  to 
the  tailings  pile.  In  all  cases  they  are  used  on  a  flat  grade,  so  that  a  front 
door  is  required  to  hold  the  load  in  place.  The  body  of  the  car  is  made  of 
2-in.  oak,  lined  on  the  inside  with  No.  12  plate  and  held  together  by  iron 


CARS 


437 


straps  at  the  end  and  middle.  The  wheels  are  keyed  to  the  axles  and  the 
axles  rotate  in  bearing  pieces  of  hickory.  The  bridle  is  fastened  by  side 
straps  D  to  a  crosspiece  of  round  iron  E  at  the  rear  end  of  the  car.  Guide 
pieces  A  are  bolted  to  the  sides  near  the  front  end,  so  as  to  guide  the 
straps  back  down  the  sides  of  the  car  in  case  they  move  above  the  sides 
when  dumping.  Brackets  B  are  also  provided  for  the  bridle  straps  to 
rest  on  while  the  car  is  being  filled  and  while  the  cable  is  slack.  As  the 
car  dumps  by  the  raising  of  the  rear  wheels  above  the  line  of  the  track,  the 
tread  of  the  back  wheels  is  made  wider  than  that  of  the  front  wheels. 
This  is  effected  by  putting  two  separate  wheels  on  the  rear  axle,  the  out- 
side wheels  on  each  side  being  loose.  On  this  account,  no  special  wide- 
faced  wheels  have  to  be  cast  for  these  skip  cars.  Because  the  grades  are 
flat,  the  cars  have  to  be  fitted  with  a  front  door.  This  is  latched  by  the 


Side  Elevation  Rear  Elevation 

FIG.    355. SKIP    CAR    USED    ON    THE    SURFACE    IN    THE    JOPLIN    DISTRICT. 


bridle  which,  after  the  car  dumps,  drops  down  on  one  or  two  bracket 
pieces  C,  bolted  to  the  door  of  the  car.  The  dump  consists  of  two  timbers 
put  up  at  such  an  angle  that  the  rear  end  of  the  car  is  raised  about  4  ft.  in 
a  distance  of  about  10  ft.,  and  owing  to  the  slow  speed  with  which  the  car 
is  hoisted  into  the  dump,  no  attempt  is  made  to  ease  the  shock  by  curving 
the  dump  track.  The  raising  of  the  rear  end  of  the  car  raises  the  cable 
and  lifts  the  bridle  off  the  brackets,  unlatching  the  doors.  When  the  car 
is  lowered  back  out  of  the  dump,  the  bridle  drops  as  the  rear  end  of  the 
car  falls  and  the  door  is  again  locked  in  place. 

Roller  Barrow. — The  roller  barrow  shown  in  Fig.  356  has  a  capacity 
of  3  cu.  ft.,  or  about  Y±  ton  of  magnetite  ore,  and  weighs,  empty,  125  Ib. 
This  type  of  barrow  is  supplanting  the  ordinary  wheelbarrow,  which  must 
frequently  be  used  in  mining  portions  of  the  flat-dipping  orebodies  at 
Mineville,  N.  Y.  The  wide  roller,  which  will  nicely  ride  a  plank,  together 
with  the  low  center  of  gravity,  obviates  the  usual  strain  in  the  wheeler's 
arms  to  keep  the  barrow  from  tipping  sideways.  The  barrow  is  generally 


438 


DETAILS  OF  PRACTICAL  MINING 


dumped  endways,  the  nose  acting  as  the  turning  point,  and  braking  is 
accomplished  by  lowering  the  handles  until  the  roller  boxes  or  rear  end 
of  the  barrow  touch  the  runway.  The  wooden  roller,  boxes  and  handles 


r* 


PIG.    356. UNDERGROUND   SINGLE-ROLLER  BARROW. 

are  easily  replaced  when  broken.     The  J-^-in.  boiler  plate- is  cut  from  a 
single  sheet,  bent  to  slope  and  the  laps  riveted. 

Truck  for  Lowering  Timber. — The  truck  shown  in  Fig.  357  is  designed 
for  lowering  timber  into  a  mine  through  an  inclined  shaft;  in  this  particu- 


Side  Elevation 
PIG.    357. — TIMBER  TRUCK   FOR   40°   INCLINE    SHAFT. 

lar  instance  the  shaft  for  which  the  truck  was  designed  had  an  inclination 
of  40°  from  the  horizontal.  The  truck  can  be  readily  made  by  the  mine 
carpenter  and  blacksmith.  Bail,  bridle,  wheels  and  axles,  similar  to  those 


CARS 


439 


of  an  ore  skip,  are  used.  The  truck  consists  of  a  platform  mounted  upon 
wheels  and  axles.  To  the  back  part  of  the  truck  upright  timbers  are 
attached,  against  which  the  ends  of  the  timbers  being  lowered  rest.  The 
timbers  on  the  platform  are  held  in  place  by  the  side  uprights  of  which 
there  are  three  on  each  side. 

ACCESSORIES 

Car  Wheels  for  Sprag  Braking. — In  the  development  of  a  flat  ore  de- 
posit with  an  extremely  irregular  floor,  such  as  is  found  in  the  lead  district 
of  southeastern  Missouri,  heavy  and  changing  grades  are  frequently  un- 
avoidable. Where  animal  haulage  is  used  in  such  mines,  some  method  of 
holding  the  cars  in  check  is  necessary.  The  ordinary  brake  beam  does 


^ffff 

IH'I<- 


/~-^*fc^L>  T     £~ 

?  *      Y     .     > 


t> 


\SteeIaxIefotie 


_Ji_    L       >/"        \  pressed  in 

K-  ^  ;>) 

'      ^'  ^  f   I  XJ 


KW                                                                                        J 
....                          ..                                .-.#             ...                                                         .....^ 
^* - •=>! 

PIG.    358. MANGANESE-STEEL   CAB    WHEEL    USED   BY    FEDERAL    LEAD    CO. 


not  operate  successfully  on  steep  grades  and  the  method  sometimes  used 
of  making  the  animal  help  is  hard  on  the  animal.  The  method  often 
followed  in  such  cases  is  to  design  the  car  wheels  with  heavy  spokes 
between  which  the  driver  shoves  a  pin  so  as  to  lock  or  sprag  the  wheel  and 
cause  the  cars  to  skid  down  the  grade  with  as  many  wheels  locked  as 
necessary.  The  driver  picks  up  the  sprag  pins  at  the  top  of  the  grade  and 
moves  from  car  to  car  locking  the  wheels.  On  the  return  trip  the  pins 
are  thrown  off  at  the  head  of  the  grade.  Cast-steel  wheels  were  used  for  a 
time  by  the  Federal  Lead  Co.,  but  proved  unable  to  withstand  the  severe 
shocks  caused  by  spragging.  This  company  has  now  adopted  manganese- 
steel  car  wheels  of  the  pattern  shown  in  Fig.  358.  These  wheels  are  used 
on  1.4-ton  cars  and  no  trouble  has  been  experienced  by  their  failure. 


440 


DETAILS  OF  PRACTICAL  MINING 


Device  for  Retarding  Speed  of  Cars  (By  John  T.  Fuller)  .—Fig.  359 
shows  the  essential  details  of  a  simple  device  for  checking  or  retarding  the 
speed  of  cars  used  at  the  diamond  mines  in  Kimberley,  South  Africa. 
It  consists  of  a  platform  built  of  one  or  more  pieces  of  timber,  bolted  or 
spiked  to  the  ties  between  the  rails,  with  a  slope  at  each  end  as  shown. 
Over  this  platform  wrought-iron  or  steel  plates  %  or  %  in.  thick  are  spiked, 
bolted  or  screwed.  The  height  of  this  platform  above  the  rail  is  just 
sufficient  to  raise  the  wheels  of  the  car  free  from  the  rail  when  the  axles 
come  into  contact  with  the  platform.  The  car  travels  the  length  of  the 
platform  on  its  axles,  its  speed  being  gently  and  gradually  checked  to  any 
degree  desired  depending  on  the  original  speed  and  the  length  of  the  plat- 


n         rn 

rn         n         rn 

n         r 

n 

i         i   i 

ii         ii         ii 

i   i         i 

^  B  > 

™    *     A    "   --"•" 

i         i   i 

ii                 ii                ii 

i      i                 i 

PIG.    359. KIMBERLEY   CAR   CHECK. 

form.  The  width  of  the  platform  will  depend  on  the  width  C  of  the 
journal  boxes.  The  length  of  the  platform  must  be  determined  by  experi- 
ment for  each  case;  but  this  is  quickly  and  easily  done.  The  length  B  of 
the  inclined  portion  of  the  platform  is  usually  about  3  ft.  and  there  have 
been  used  at  different  places  platforms  with  the  length  A  from  10  to  25  ft. 
When  once  properly  adjusted  this  car  check  will  be  found  not  only  simple 
and  economical  but  absolutely  automatic  and  indestructible  under  the 
roughest  usage.  This  device  can,  of  course,  be  used  only  where  the  car 
axles  are  free  to  revolve.  Contrary  to  expectation,  there  has  been  experi- 
enced no  trouble  with  bent  axles  by  using  this  form  of  check. 

Lever  and  Lock  for  Side -dump  Car. — The  typical  car  for  underground 
electric  haulage  on  the  iron  ranges  has  a  gable  bottom  and  side  dump, 
holds  from  2  to  3  tons  and  is  mounted  on  a  single  truck.  The  devices  for 
locking  and  releasing  the  side  door  are  as  numerous  as  the  .companies 


CARS 


441 


_± 


442 


DETAILS  OF  PRACTICAL  MINING 


operating.  One  of  the  best  is  that  used  in  the  Oliver  mines  at  Ely,  Minn., 
illustrated  in  Fig.  360.  Two  levers  with  spring  stops,  similar  to  the  brake 
and  clutch  levers  on  small  hoists,  are  mounted  on  opposite  ends  of  the  car, 
so  that  one  operates  each  door.  As  the  train  comes  to  the  pocket,  two 
men  take  position  on  opposite  sides  of  the  track  and  release  the  levers  so 
as  to  open  the  doors  as  the  cars  pass,  the  operation  being  extremely  rapid. 
The  weight  of  the  ore  swings  open  the  door  so  as  to  permit  a  free  discharge 
and  any  material  that  sticks  to  the  bottom  is  released  by  banging  the 
doors  vigorously.  Each  lever  is  keyed  to  a  1^-in.  horizontal  shaft  ex- 
tending the  length  of  the  car  under  the  inclined  bottom.  This  shaft 
works  in  three  one-piece  cast-iron  boxes  fastened  to  the  underside  of  the 


Corner  of  Car 


I  Staple - 


,-Top  of  Rait 


FIG.   361. — KENNEDY  CAR   GRIP. 


car  bottom  in  an  inclined  position.  Three  hooks  are  also  keyed  to  the 
shaft  and  their  ends  engage  the  lower  edge  of  the  door.  A  handle,  spring 
and  sliding  stop  are  fitted  to  the  lever  in  the  ordinary  manner,  the  stop 
engaging  notches  in  an  arc  which  is  held  out  from  the  end  of  the  car  by 
bolts  and  spacers  and  which  passes  through  a  slot  in  the  lever.  In  locking 
the  door,  the  lever  is  forced  well  along  the  arc  and  when  the  stop  enters  a 
notch,  there  is  enough  spring  in  the  lever,  keys  and  shaft  to  keep  the 
hooks  tight  against  the  door.  The  arrangement  and  dimensions  are 
shown  in  the  drawing. 

Latch  for  Holding  Car  During  Loading. — At  the  Kennedy  mine  on  the 
North  Cuyuna  range,  the  device  represented  in  Fig.  361  is  in  use  for 
holding  cars  while  loading  from  a  chute,  in  cases  where  the  grade  might 
otherwise  cause  the  car  to  run  away.  The  drawing  is  an  elevation  taken 
diagonally  across  the  drift.  The  bar  is  held  to  a  drift  post- by  a  staple 


CARS 


443 


and  is  of  such  a  length  that  when  it  is  caught  in  a  corner  of  the  car,  the 
latter  is  properly  positioned  for  loading  from  the  chute. 

Car -bottom  Straightener. — In  loading  cars  from  stope  chutes,  espe- 
cially where  stoping  is  done  by  the  shrinkage  system,  the  falling  of  large 
pieces  of  ore  batters  the  bottoms  of  the  car  boxes  out  of  shape.  These 
car  bottoms  must  be  straightened  from  time  to  time,  and  in  Fig.  362  is 
shown  a  device  which  works  much  better  than  the  time-honored  sledging 
method.  A  frame,  3  X  7  ft.  in  the  clear,  is  constructed  of  a  6  X  6-in. 


y//////////////. 

FIG.   362. — SINGLE-SCREW    COLUMN    FOR    STRAIGHTENING    CAR    BOTTOM. 

sill,  two  4  X  4-in.  posts  and  a  6  X  6-in.  cap,  the  whole  held  securely 
together  by  two  J^-in.  tie-rods,  and  firmly  braced.  The  car  box,  the 
bottom  of  which  needs  straightening,  is  removed  from  its  truck  and 
placed  under  the  frame,  bottom  side  up.  A  single-screw  drill  column  is 
then  set  up  as  shown,  and  pressure  brought  to  bear  on  the  box.  By 
applying  this  pressure  in  two  or  three  places,  if  necessary,  the  bottom  is 
pressed  back  into  shape  without  the  denting  and  local  strains  which  sledg- 
ing would  cause. 


XI 

TRACK 
Track  Arrangement — Laying  Track — Switches,  Etc. 

TRACK  ARRANGEMENT 

Track  Work  in  a  Minnesota  Mine  (By  E.  W.  R.  Butcher)  .—Fig.  363 
shows  some  details  of  underground  track  work  and  one  of  the  motor 
turns  used  in  the  mines  of  the  Republic  Iron  &  Steel  Co.,  on  the  Mesabi 
range.  A  right  and  left  turn  is  shown  in  1  and  2.  As  a  rule,  the  location 
of  a  turn  is  determined  before  the  drift  is  driven  and  the  necessary  sets  are 
put  in  place  to  make  the  turn  when  required.  Props  are  placed  under  the 
ends  of  the  two  caps  resting  on  the  opening  set  until  that  turn  is  to  be  driven. 
A  9-ft.  by  6-in.  post  is  used  under  both  of  these  caps  and  on  either  side 
the  posts  of  each  set  are  shortened  6  in.  until  an  8-ft.  post  is  reached,  which 
is  the  length  of  post  used  in  motor  drifts.  When  the  opening  set  is  placed 
in  position,  a  point  is  placed  on  the  set  and  on  the  10-ft.  by  9-in.  set  and 
with  this  line  the  rest  of  the  turn  is  put  in  with  the  aid  of  the  other  dimen- 
sions shown.  In  3,  4  and  5  are  shown  the  track  layout  and  frog  details 
used  in  connection  with  a  25-ft.-radius  timber  turn.  The  frog  is  de- 
signed so  that  it  can  be  used  for  either  a  right  or  a  left  turn.  The  stub 
switch  has  given  better  satisfaction  for  underground  work  than  the  point 
switch.  The  latter  caused  considerable  trouble  by  dirt  getting  between 
the  wing  rail  and  track,  which  interfered  with  its  closing.  In  6  to  10, 
inclusive,  are  shown  the  details  of  switch  stand  and  tie-rod  connections. 

Tracks  for  Loading  Station. — In  the  mines  of  the  St.  Louis  Smelting 
&  Refining  Co.,  in  southeastern  Missouri,  a  three-track  approach- to  the 
shaft  is  used,  since  the  ground  stands  well  and  the  shaft  station  may  be 
made  extra  wide.  The  1-ton  cars  are  drawn  by  an  electric  motor  in 
trains  on  tracks  of  24-in.  gage.  The  loaded  cars  are  pushed  in  trains 
ahead  of  the  locomotive,  on  to  the  middle  track,  while  empty  cars  are 
pulled  from  the  cages  and  are  generally  put  on  the  outside  tracks.  The 
drift  end  of  the  three-track  approach,  which  is  100  ft.  long  in  some  in- 
stances, has  to  be  fitted  with  a  three-way  switch,  as  shown  in  Fig.  364, 
at  the  point  where  the  two  tracks  make  off  from  the  single  track.  The 
curves  on  this  track  can  be  made  easy.  The  arrangement  of  the  track 
and  the  frogs  is  shown.  At  the  loading  end  of  the  three-track  approach, 

444 


TRACK 


445 


the  crossovers,  as  shown  in  Fig.  365,  have  to  be  made  abrupt,  so  that  the 
switching  from  one  track  to  the  other  may  be  done  in  the  minimum  of 


K—  81  — H 


<- -22 -  -  —  -  -  -  - 

^9-TJE  ROD  FOR  POINT  SWITCH  (56"(SAGE) 


JO-TIE  ROD  FOR  STUB  SWITCH  . 

FIG.    363. REPUBLIC    IRON    &    STEEL    TURNOUT   TRACK    AND    SWITCHES. 

space  and  as  near  the  shaft  as  possible,  to  decrease  the  distance  that  the 
cagers  must  walk  in  getting  an  empty  car  and  a  loaded  car  off  the  cage. 
In  the  drawings  the  dimensions  are  given  which  have  been  found  best  for 


446 


DETAILS  OF  PRACTICAL  MINING 


loading  cages  at  greatest  speed.  At  first  a  distance  of  13  ft.  from  the  shaft 
to  point  of  middle  frog  was  tried,  but  this  was  found  to  be  too  great  and 
was  shortened  to  11  ft.  This  has  been  found  to  be  just  about  right,  the 
curve  beginning  almost  as  soon  as  the  cars  clear  the  shaft.  The  distance 
between  outside  rails  in  the  three-track  straightway  is  11  ft.  This  gives 
plenty  of  clearance  between  cars.  In  the  loading  crossovers  a  kick 


I 

.-Main  Track 


•About  SO 


Empty   Cars 
L oaded  Cars 


Loaded  Cars        Tv 


.-Switch 


Cars 


FIG.    364. DRIFT  END  AND  THREE-WAY  SWITCH  FOR  TRIPLE-TRACK  LOADING  STATION. 

switch  is  needed  to  join  the  middle  track  with  the  track  that  connects  it 
with  the  shaft,  shown  in  Fig.  365.  The  cagers  throw  this  with  one  foot  and 
after  running  the  empty  car  out  on  the  outside  track  on  the  same  side  of 
the  shaft  that  it  came  from,  cross  over  to  the  center  track  to  get  the  loaded 
car. 


FIG.    365. CONNECTIONS     BETWEEN     TWO-COMPARTMENT     SHAFT     AND      THREE-TRACK 

STATION. 

Economical  Incline  Track  Arrangement. — The  working  shaft  of  the 
Sterling  Iron  &  Ry.  Co.,  at  Lakeville,  N.  Y.,  is  in  the  orebody  and  follows 
approximately  the  flat-dipping  foot-wall.  The  foot-wall  is  extremely 
irregular  and  while  some  of  the  rolls  are  followed  by  the  shaft,  it  was 


TRACK 


447 


necessary  to  cut  through  some  of  the  sharper  ones.  In  order  to  reduce 
the  width  of  these  cuts  and  also  to  save  a  certain  amount  on  rails  and  ties, 
a  rather  ingenious  method  of  arranging  the  tracks  was  resorted  to,  as 
shown  in  Fig.  366.  Hoisting  is  done  in  balance  from  several  levels  so 
that  provision  had  to  be  made  for  the  skips  to  pass.  From  the  top  of  the 
headframe  to  the  800-ft.  point,  three  rails  are  used.  This  is  not  an  un- 
usual method  on  inclined  planes  and  results  in  saving  the  cost  of  one  rail,  a 


FIG.    366. ECONOMIZING    EXCAVATION   IN   INCLINE    DOUBLE-TRACK    SHAFT. 

certain  amount  in  the  length  of  the  ties  and  some  rock  cutting.  At  the 
800-ft.  point  a  change  is  made  to  four  rails,  two  complete  tracks,  in  the 
manner  shown,  no  switch  being  necessary.  The  tracks  are  continued  to 
the  1600-ft.  point  and  the  two  skips  can  pass  anywhere  between  these 
points.  From  the  1600-ft.  point  down,  it  was  desired  to  carry  the  shaft 
as  narrow  as  possible,  but  the  management  was  unwilling  to  risk  possible 
accident  from  the  use  of  the  switch  which  would  have  become  necessary 


448  DETAILS  OF  PRACTICAL  MINING 

if  a  single  track,  that  is,  two  rails  were  there  used.  The  safety  of  a  hand- 
operated  switch  at  such  a  point  depends  on  the  memory  of  the  operator  as 
to  which  track  the  last  skip  was  sent  over,  and  an  automatic  switch  is 
liable  always  to  get  out  of  order.  The  scheme  illustrated  was  conceived 
and  has  given  excellent  satisfaction.  While  it  uses  four  rails,  no  increase  in 
the  length  of  the  ties  is  necessary  and  not  much  in  the  width  of  the  cut  over 
that  required  for  a  single  track  and  the  saving  over  the  three-rail  system 
used  in  the  upper  part  of  the  shaft  is  appreciable.  No  switch  is  required 
at  the  1600-ft.  point  to  change  to  the  two-track  portion.  The  arrange- 
ment continues  to  the  bottom  of  the  shaft  at  2650  ft.  below  the  collar. 
There  are  no  compartments  in  the  shaft,  no  timber  whatever  being 
required  with  the  excellent  hanging;  the  shaft  is  quite  open,  really  a  part 
of  the  stopes  in  places. 

Track  Spreader  and  Guard-rail  Bracket. — The  type  of  track  spreader 
shown  in  Fig.  367  is  particularly  useful  for  keeping  the  rails  to  gage  on 
timber  stringers  which  have  become  partially  rotten,  so  that  they  will 
not  hold  a  spike  securely.  Of  course,  the  surest  remedy  is  to  replace  the 
stringers,  but  often  the  use  of  a  track  spreader  will  keep  the  skipways  in 


FIG.    367. TEMPORARY   REPAIR   FOR   ROTTEN    SKIP    STRINGER. 

commission  until  holidays,  when  stringers  can  be  replaced  without  inter- 
rupting the  mine  output.  A  %  X  6-in.  flat  iron,  bored,  for  J^  X  2J^  X  4- 
in.  clips,  is  driven  under  both  rails  after  sufficient  rotten  timber  has  been 
cut  away,  as  seen  in  the  illustration.  The  clips  are  then  bolted  to  the  flat 
iron.  This  will  keep  the  track  to  gage,  even  though  the  rails  may  move 
to  the  sides  of  the  stringers.  To  keep  the  rails  centered  on  the  timber, 
^  X  6  X  6-in.  clips  may  be  bolted  to  the  bottom  of  the  spreader  and 
wood  blocks  can  be  driven  between  the  clip  and  the  stringer,  the  stringers 
being  kept  the  proper  distance  apart  by  the  usual  3  X  6-in.  spreader  held 
by  a  girt  rod.  To  save  the  cable,  rollers  are  used  near  the  iron  spreaders. 
Brackets  of  Y±  X  6-in.  flat  iron,  to  hold  the  back  or  guard  rail,  may  be 
bolted  to  the  projecting  ends  of  the  track  spreader.  The  same  type  of 
bracket  on  new  skip- ways  is  made  longer  by  an  amount  equal  to  the  depth 
of  the  stringer,  and  bolted  to  the  wall  plates,  which  are  usually  introduced 
at  15-ft.  intervals. 


TRACK 


449 


Track  Curves  in  Top -slice  Rooms. — In  the  top-slice  method  of  ore 
extraction  as  practised  on  the  Mesabi,  successive  rooms  are  opened  off  the 
crosscut,  extending  10  ft.  one  way,  and  40  ft.  the  other.  The  track  from 
the  crosscut  is  turned  into  the  long  side  of  the  room  only.  For  the  first 
room  mined  from  any  crosscut,  a  curve  is  fitted  into  the  track  such  as  rep- 
resented by  the  portions  of  the  rails  A-A',  Fig.  368.  When  the  room  is 
mined  and  caved,  the  track  is  taken  out  and  it  is  desirable  to  use  the  same 
curved  portion  for  laying  track  into  the  next  room.  It  is  only  rarely 
that  the  break  in  the  crosscut  rails  is  such  that  the  curve  will  fit.  The 
difficulty  is  overcome  by  Captain  James  Rosewall  of  the  Harold  mine  by 
using  two  switch  points,  as  shown.  The  curve  rails  are  laid,  the  portions 
B  of  the  crosscut  rails  are  spread  apart  and  the  switch  points  fitted  in  to 


FIG.    368. FITTING    TRACK    INTO    ROOM    FROM    CROSSCUT. 

make  a  tight  and  smooth  joint.  The  switch  points  used,  of  course,  are 
such  as  would  be  used  for  a  split  or  fixed  switch  and  not  for  a  stub  switch. 
The  trick  is  one  taken  from  openpit  practice,  where  in  changing  tracks  it  is 
often  difficult  to  get  joints  to  match  without  recourse  to  this  device. 


LAYING  TRACK 

Convenient  Grade  Stick  (By  Edward  H.  Orser). — The  grade  stick 
shown  in  Fig.  369  is  a  handy  form  of  one  of  the  most  useful  tools  in  the 
trackman's  equipment.  It  consists  of  a  1  X  6-in.  board  fitted  with  two 
iron  angle  shoes  at  the  ends,  the  middle  part  of  the  top  of  the  board  being 
straight  and  true  and  parallel  with  the  bottom.  A  hand-hole  is  cut  as 
shown  and  the  ends  of  the  top  are  beveled  off  to  reduce  weight.  The 
shoes  on  both  ends  are  the  same,  but  are  placed  in  opposite  positions  the 

29 


450  DETAILS  OF  PRACTICAL  MINING 

short  leg  turning  up  in  one  case  and  down  in  the  other.  This  short  end  is 
made  of  a  length  to  give  the  exact  grade  desired;  for  example,  if  a  0.5  per 
cent,  grade  is  wanted  and  the  grade  stick  is  8  ft.  4  in.  long,  the  length  of 
the  short  leg  of  the  shoe  will  be  J£  in.  In  drifting,  the  left  end  is  kept 
ahead.  When  a  new  section  of  track  is  to  be  laid,  the  back  end  of  the 
grade  stick  is  set  on  one  rail  and  a  hand  level  placed  on  the  flat  top. 
The  new  rail  is  raised  until  the  bubble  is  centered.  If  on  straight  track, 
the  other  rail  is  set  by  leveling  across.  If  on  a  curve,  the  proper  allowance 
for  raise  is  made  in  the  outside  rail.  If  the  level  is  out  of  adjustment,  it 


r 


Shoes  made  ofJ$  "iron',  set  in  flush  with  bottom  of  stick. 

A,  varied  to  give  grade  desired,  ffo/es  spaced  2  "apart,  ^."dictm. 

FIG.    369. IRON-SHOD    GRADE    STICK    FOR   MINE    TRACKS. 

should  be  reversed  and  the  new  rail  lowered  or  raised  so  as  to  split  the 
difference. 

Angle-iron  Track  Gage. — A  serviceable  track  gage  can  be  made  from 
a  piece  of  angle  iron  as  shown  in  the  accompanying  drawing,  Fig.  370. 
One  leg  of  the  angle  is  cut  away  flush  with  the  face  of  the  other  leg  and 
back  from  the  ends  3  in.  The  remaining  length  of  this  leg  gives  the 
proper  gage  for  the  track  and  the  3-in.  projections  of  the  other  leg  rest  on 
top  of  the  rails.  A  J^-in.  round  handle  riveted  on  the  upper  or  longer  leg 
of  the  gage  makes  it  complete.  With  a  little  use  track  gages  constructed 


2i"xj  Angle  Iron 

Gage --^j'H 

FIG.    370. STIFF    GAGE-IRON    FOR   TRACK    LAYING. 

of  wood  soon  become  so  badly  battered  that  they  are  practically  useless 
and  those  made  of  iron  are  easily  bent,  thus  giving  in  both  cases  a  distance 
shorter  than  the  gage  desired  for  the  track  being  laid. 

Bending  Rails  with  Screw-jack  (By  A.  Livingstone  Oke). — There  is 
illustrated  in  Fig.  371  a  method  for  bending  rails,  consisting  of  the  use  of  a 
screw-jack  in  conjunction  with  three  upright  posts  planted  in  the  ground 
to  form  the  apexes  of  an  isosceles  triangle,  as  shown.  The  rail  to  be  bent 
is  placed  across  two  of  the  posts  and  the  jack  is  footed  against  the  third. 
To  facilitate  the  manipulation  of  the  jack  and  rail,  it  is  desirable  to  use 


TRACK 


451 


three  blocks  of  wood,  the  longer  one  slightly  inclined  on  its  upper  surface 
to  form  a  rest  for  the  jack,  and  the  other  two  notched  to  receive  the  side  of 
the  rail  and  give  a  steady  support.  To  prevent  the  movement  outward 
of  the  tops  of  the  posts,  three  links  are  made  with  eyes  at  the  extremities, 
which  drop  over  round  iron  dowels  driven  firmly  in  the  tops  of  the  posts. 
The  lower  ends  of  the  posts  are  sunk  from  1  to  2  ft.  in  the  ground.  This 
device  has  been  found  useful  in  mines,  as  it  is  possible  to  place  posts 
arranged  in  this  manner  at  entrances  and  at  suitable  points  underground, 


FIG.    371. POSTS    AND    RESTS    FOR    SCREW-JACK    RAIL   BENDER. 

where  frequent  rail-bending  is  necessary,  and  thus  avoid  the  transporta- 
tion of  the  usually  heavy  jim-crow,  the  lighter  screw-jack  being  all  that 
is  required  to  carry  about. 

Notched-log  Rail  Bender  (By  Charles  F.  Spaulding). — A  sturdy 
and  handy  device  for  bending  rails  can  be  made  of  two  logs,  a  6  X  6-in. 
piece  and  a  screw-jack,  as  shown  in  Fig.  372.  The  logs  are  laid  side  by 
side  and  two  notches  cut  at  opposite  points  in  each.  In  one  pair  of  these, 
the  6  X  6-in.  piece  is  wedged.  In  the  other,  the  rail  is  laid.  The  dis- 


452 


DETAILS  OF  PRACTICAL  MINING 


FIG.   372. — BAIL-BENDER   OP   SCREW-JACK   AND   ROUND   TIMBER. 


PIG.    373. LEVER   PORK   FOR   HOLDING   TIE   TO    RAIL. 


TRACK  453 

tance  between  notches  along  the  logs  should  be  such  that  a  IJff-in.  or 
IJ^-in.  jack,  footed  against  the  crosspiece,  will  easily  reach  the  rail. 
For  curves  of  different  radius,  the  logs  can  be  laid  a  greater  or  less  distance 
apart. 

Rail  and  Tie  Holder. — In  laying  or  repairing  mine  tracks,  it  is  not 
always  possible  to  have  the  rails  resting  upon  all  the  ties  before  spiking, 
due  to  the  unevenness  of  drift  and  crosscut  floors.  To  overcome  the 
difficulty  of  spiking  under  such  conditions,  the  tool  shown  in  Fig.  373  was 
devised.  One  end  of  a  2-ft.  length  of  IJ^-in.  octagon  drill  steel  was  split 
for  1  ft.  and  shaped  into  a  fork,  the  end  of  each  prong  for  a  length  of  4  in. 
being  bent  forward  at  a  right  angle;  the  other  end  of  the  drill  steel  was 
drawn  out  so  that  it  would  just  slip  into  a  piece  of  1-in.  pipe;  this  pipe 
serves  as  a  handle  and  lever.  By  placing  the  fork  over  a  rail  and  slipping 
the  prongs  under  a  tie,  the  latter  may  be  held  up  firmly  against  the  rail 
while  being  spiked. 

SWITCHES,  ETC. 

Switches  and  Crossings  (By  D.  W.  Jessup). — In  underground  track 
work,  where  there  is  heavy  traffic,  the  switches  in  general  use  are  the  stub 
and  split  switches  and  their  modifications.  These  switches  are  operated 
in  various  ways;  usually  by  means  of  a  stand  and  lever,  a  crank  and  lever, 
a  toggle  joint,  or  a  target.  Where  light  traffic  is  concerned,  especially 
a  one-car  traffic,  the  switch  is  operated  by  the  hand  or  a  kick  of  the  foot 
and  gives  satisfactory  results.  In  laying  track  it  is  important  to  remem- 
ber that  the  frog  should  be  elevated  about  Y±  in.  above  the  rails,  as  this 
throws  the  car  against  the  rail  opposite  the  frog  and  prevents  the  car 
wheels  from  catching  the  frog. 

Fig.  374,  at  1,  illustrates  a  typical  stub  switch  with  a  turnout  BB  from 
the  main  track  A  A.  The  switch  points  at  CC  are  held  together  by  means 
of  a  bridle  D  and  fit  into  slots  as  shown  in  2;  with  a  broader  gage  more 
than  one  bridle  is  often  used.  The  bridle  is  moved  to  and  from  A  A  to 
BB  by  various  lever  methods,  principally  by  those  given  above.  The 
throw  or  movement  of  the  switch  rails  for  an  18-in.  gage  is  about  1 J^  in. 
and  a  J£-in.  space  is  left  between  the  switch  point  ends  to  allow  for  easy 
shifting.  Allowance  for  movement  of  the  switch  rails  CC  must  be  made ; 
these  rails  are  not  spiked  for  a  distance  of  12  or  15  ft.  back  from  the  switch 
points,  and  to  replace  the  spikes,  clamps  E  are  placed  about  every  3  ft. 
from  the  points.  Underneath  the  switch  points  is  placed  a  long,  solid 
6  X  6-in.  tie,  which  extends  to  the  switch  levers,  and  facilitates  the  move- 
ment of  the  rails.  To  prevent  wearing,  a  strip  of  sheet  iron  3  or  4  in. 
wide  is  fastened  to  the  tie  underneath  the  points. 

The  typical  railroad  split  switch  is  but  little  used  underground  in 
metal  mines,  except  with  a  track  of  broad  gage,  and  in  mines  with  a  large 


454 


DETAILS  OF  PRACTICAL  MINING 


'<**      PLAN  OF  EXTENSION  SWITCH  ECCENTRIC       * 


DIAMOND  CROSSOVER  OPEN  CROSSOVER  SI MGLE  CROSSOVER 

FIG.    374. SWITCHES    AND    TRACK   EQUIPMENT    ADAPTED  FOR   MINE    USE. 


TRACK  455 

traffic,  since  it  is  expensive  to  make  and  lay,  and  is  not  adapted  to  short 
turns.  A  modified  split  switch  is  used  as  shown  in  3.  Two  latches 
A  A'  are  fastened  to  the  rails  BB',  and  are  held  together  by  a  clamp  D 
and  a  bridle  C.  The  latches  vary  in  length  from  24  to  36  in.  and  are 
drawn  to  a  point  at  one  end,  flattening  the  outside  and  leaving  the  inside 
about  normal,  or  slightly  curved  inward,  the  length  of  the  taper  depend- 
ing upon  the  length  of  the  turnout.  The  bridle  is  operated  by  one  of  the 
different  switch  levers. 

The  stand-and-lever  switch  is  found  in  operation  in  many  mines  and 
affords  satisfaction.  It  has  the  advantage  over  the  crank  and  lever  in 
that  it  offers  some  latitude  in  the  throw  of  the  switch,  as  is  often  demanded 
in  the  double  turnout  or  in  cases  where  the  rails  spread  and  the  switch 
points  are  not  in  line,  while  the  crank  and  lever  offers  but  one  distance  of 
throw.  The  stand  is  spiked  to  a  6  X  6-in.  tie  which  extends  under  the 
switch  points,  as  shown  in  4,  and  is  placed  about  18  in.  from  the  track, 
allowing  sufficient  space  so  that  a  car  running  on  the  track  will  not  strike 
the  lever  arm  or  stand.  The  latter  is  about  20  in.  wide  and  12  in.  high, 
consisting  of  a  double  frame  A  made  from  %  X  IJ^-in.  iron,  the  halves 
spaced  J£  in.  apart,  and  riveted  together  at  H  and  G.  About  2  in.  of 
each  leg  is  turned  out  and  fastened  to  the  tie  by  lag  screws  as  shown,  and 
a  double  strap  B  is  riveted  across  the  frame  about  4  in.  above  the  bottom. 
The  lever  arm  C  passes  between  these  straps  and  is  fastened  to  them  by 
a  loose  bolt  or  a  pin  at  D,  about  which  the  lever  is  pivoted.  The  length 
of  the  lever  is  from  24  to  36  in.  and  the  lever  is  bent  inward  so  that 
a  passing  car  will  not  strike  it ;  the  lever  is  held  in  place  by  a  pin  passing 
through  the  holes  E  in  the  stand.  The  lower  end  of  the  lever  is  fastened 
to  the  switch  rod  by  a  bolt  or  pin,  the  rod  extending  to  the  bridle.  The 
stand  is  sometimes  made  so  that  the  legs  are  spiked  to  the  sides  of  the  tie 
instead  of  the  top,  but  it  then  lacks  stability. 

The  crank-and-lever-arm  method  of  movement  is  shown  in  3.  An 
arm  or  switch  lever  about  18  in.  long  is  fastened  to  the  bridle  at  E,  and 
the  other  end  is  fastened  to  the  crank  shaft  at  F.  The  throw  of  the  crank 
should  be  exactly  equal  to  one-half  the  throw  of  the  switch.  The  length 
of  the  crank  shaft  is  about  4  in.;  it  is  attached  to  a  block  or  tie  by  means 
of  a  strap  H.  The  lever  arm  is  thrown  by  hand.  Its  length  should  be 
such  that  when  thrown  toward  the  track  it  will  not  touch  it.  The  weight 
on  the  arm  is  5  or  10  Ib.  A  piston  rod  and  chuck  from  an  old  machine 
drill  will  answer  the  purpose. 

At  times  it  may  be  convenient  to  have  the  lever  situated  at  some  dis- 
tance back  from  the  switch  points,  and  of  the  several  devices  an  eccentric 
or  a  toggle  joint  is  often  used.  The  eccentric  is  shown  in  5.  A  switch 
rod  consisting  of  a  double  strap  A  about  24  in.  long  and  extending  out 
from  the  bridle  to  a  piece  of  timber  B,  passes  over  a  lateral  strap  C,  with- 


456  DETAILS  OF  PRACTICAL  MINING 

out  being  fastened  to  it.  The  strap  A  is  riveted  in  two  places  G,  spaced 
3  in.  apart  and  about  16  in.  from  the  rail,  the  eccentric  of  the  lever  rod  D 
passing  through  the  space.  A  short  arm  E  about  8  in.  long  is  attached 
by  a  pin  or  bolt  to  the  lever  rod  D,  and  also  to  the  lateral  strap  C.  The 
eccentric  of  the  lever  rod  is  equal  to  the  throw  of  the  switch,  1J^  in.  The 
rod  is  jointed  and  extends  to  the  switch  stand.  By  operating  the  lever, 
the  eccentric  moving  between  the  rivets  G  causes  the  switch  lever  to 
move  the  track  from  either  point  of  switch. 

The  toggle  joint,  6,  is  of  simpler  construction  than  the  eccentric 
switch,  and  is  perhaps  more  satisfactory.  A  switch  lever  A  connects 
the  bridle  to  one  of  the  toggles  B;  the  toggles  consist  of  a  double  strap 
about  8  in.  long  fastened  at  C  and  to  the  lever  rod  D  by  pins  or  bolts. 
By  operating  the  lever  rod  D  the  toggles  are  pushed  in  or  out,  causing 
the  bridle  to  move  at  the  switch  points.  The  lever  may  be  of  simple 
construction  as  shown  in  7. 

The  following  switches  are  designed  mostly  for  one-car  traffic;  they 
give  satisfaction,  and  are  easy  of  manipulation,  being  adjusted  by  the 
hand  or  foot.  The  kick  or  latch  switch  is  recommended  as  being  one  of 
the  most  efficient  of  the  lighter  switches,  due  to  its  short  length,  its  dura- 
bility, and  its  easy  adjustment  by  a  kick  of  the  foot  or  a  movement  of  the 
car,  the  carman  not  finding  it  necessary  to  advance  ahead  of  his  car  to 
adjust  the  switch  unless  running  toward  it.  The  only  disadvantage  is 
that  if  repairs  are  needed  it  may  be  necessary  to  remove  the  whole  switch 
to  the  blacksmith  shop.  The  switch,  shown  in  8,  consists  of  two  short 
switch  points  or  latches  A,  20  to  24  in.  long,  fastened  to  the  rails  at  B  by 
means  of  a  looped  strap;  the  points  are  tapered  and  turned  slightly  out- 
ward. A  bridle  strap  14  to  16  in.  long  is  riveted  underneath  to  the  points 
of  the  latches,  the  holes  through  which  the  rivets  pass  being  of  larger 
diameter  than  the  rivets,  to  permit  the  movement  of  the  switch.  The 
outside  latch  is  1  or  2  in.  shorter  than  the  inside  latch,  its  length  depending 
on  the  angle  of  the  turnout.  The  looped  strap  fastening  the  latch  to  the 
rail  is  made  of  %  X  1-in.  iron,  as  shown  in  9,  and  is  bolted  to  both  sides  of 
the  rail,  the  loop  first  passing  through  the  %  X  1-in.  slot  cut  in  the  latch. 
The  latches  may  als"o  be  fastened  as  shown  in  12,  the  strap  being  bolted 
to  the  latch,  through  which  a  pin  is  driven  into  the  tie.  This  method  is 
unsatisfactory  as  the  pin  will  pull  out  and  cause  derailments.  Another 
and  better  method  of  fastening  the  latch  is  shown  in  9,  a  lug  being  made 
on  one  side  of  the  latch  through  which  a  hole  is  bored  and  a  pin  of  smaller 
diameter  driven  through  the  lug  and  into  the  tie. 

The  switch  shown  in  10  is  not  movable  and  has  no  movable  parts  that 
will  wear,  as  all  of  the  rails  are  spiked  to  the  ties.  Sufficient  space,  about 
1^2  in.,  is  allowed  between  the  main  track  and  the  rails  to  admit  the  pas- 
sage of  the  car  wheels.  The  direction  of  the  car  is  controlled  by  the  car- 


TRACK  457 

man  who  throws  the  car  to  either  track  by  a  twist;  this  is  easily  done  with 
an  empty  car  but  with  a  loaded  car  it  is  troublesome.  This  switch  is 
used  to  advantage  when  the  loaded  cars  are  running  away  from  the  switch. 
If  the  car  wheel  has  a  groove  or  double  flange  worn  on  its  face,  the  car  may 
tend  to  follow  in  the  direction  of  the  turnout.  The  railpoint  A'  should  be 
in  line  with  the  main  track,  and  as  the  point  A  may  cause  derailments,  the 
rail  at  C  is  made  lower  than  at  A';  then  the  weight  will  cause  the  car  to 
crowd  closer  to  C  and  not  tend  to  derail.  The  point  at  A  should  be  slightly 
higher  than  the  rail  at  (7,  which  will  assist  the  carman  in  throwing  the 
car  in  the  direction  of  the  turnout.  The  length  of  the  lead  rail  is  usually 
from  5  to  7  ft.,  depending  on  the  angle  of  the  turnout. 

A  special  form  of  fixed  switch  is  sometimes  used,  giving  an  unbroken 
main  line,  as  shown  in  11,  requiring  the  use  of  two  hinged  latches  E,  which 
are  about  4  in.  long  and  are  fastened  to  the  turnout  rails.  When  it  is 
desired  to  run  the  cars  over  the  turnout,  the  latches  are  placed  over  the 
main  line,  a  flange  on  the  under  side  preventing  their  slipping;  and  when 
running  on  the  main  line  the  latches  are  swung  out.  This  form  of  switch 
is  not  commonly  used;  it  is  troublesome,  as  the  latches  may  slip,  always 
takes  time  to  adjust,  and  may  accidentally  be  left  on  the  main  line, 
causing  derailments. 

The  tongue  switch,  shown  in  12,  is  used  extensively  with  tracks  over 
which  there  is  light  traffic,  but  it  is  not  recommended  for  heavy  traffic, 
though  it  is  often  used  for  such.  Derailments  frequently  happen  due  to 
an  open  switch,  or  the  pin  pulls  out  that  holds  the  tongue,  or  the  tongue 
may  turn  over  on  its  side  causing  cars  to  drop  in  between  the  rails.  The 
advantage  of  this  switch  lies  in  its  simple  construction,  the  little  repairing 
required,  and  the  ease  of  laying.  The  movement  of  the  car  will  not  throw 
the  switch  as  it  will  the  kick  switch,  and  it  is  necessary  for  the  carman  to 
advance  ahead  of  the  car  to  move  the  tongue.  The  details  of  the  switch 
are  shown  in  12 A.  The  point  of  the  tongue  is  tapered  and  curved  slightly 
outward ;  a  strip  of  sheet  iron  is  nailed  across  the  tie  over  which  the  tongue 
point  moves. 

The  three-way  switch  or  double-turnout  switch  is  used  where  two 
crosscuts  are  driven  on  opposite  sides  from  a  main  drift,  and  it  is  desired  to 
run  tracks  in  the  crosscuts  from  the  drift.  In  this  case  the  stub  switch 
will  be  used  to  best  advantage.  It  is  operated  by  a  stand  and  lever  which 
allows  the  latitude  of  movement  of  the  switch  rails  demanded  by  the 
nature  of  the  switch,  as  illustrated  in  13.  To  allow  for  the  shift  of  the 
switch  rails,  they  remain  unspiked  for  a  distance  of  15  ft.  or  more. 

Crossings  are  used  where  tunnels  or  drifts  intersect  at  right  angles  and 
it  is  desired  to  continue  the  tracks  in  the  one  direction  without  turning  on 
the  other  tracks.  The  crossing  shown  in  14  consists  of  four  ordinary 
90°  crossing  frogs  A  and  the  four  inner  crossing  rails  B  which  are  a  contimia- 


458 


DETAILS  OF  PRACTICAL  MINING 


tion  of  the  tracks;  the  latter  have  a  length  of  15J/2  in.  leaving  a  space  of 
\Y±  in.  between  the  point  of  frog  and  the  point  of  crossing  rail.  An  inner 
guard  rail  or  square  section  C  is  often  used,  affording  a  more  satisfactory 
track.  If  the  traffic  is  much  heavier  over  one  of  the  tracks,  and  it  is 
desired  to  have  the  rails  remain  unbroken,  then  the  track  over  which  there 
is  lighter  traffic  is  raised  1^  or  2  in.  above  the  other  track,  and  hinged 
latches  4  or  5  in.  long  are  swung  over  the  main  track  to  connect  with  the 
inner  crossing  rails  when  the  lighter  traffic  track  is  to  be  used.  When  not 
using  this  track  the  latches  are  swung  back  again  leaving  the  main  track 
clear.  But  there  is  always  the  disadvantage  of  misplaced  latches  which 
give  trouble. 

A  double  crossover  from  one  track  to  a  parallel  track  is  sometimes 
demanded.  In  15  is  illustrated  the  diamond  crossover,  one  of  the  many 
kinds  in  common  use.  The  switch  points  are  fixed,  there  being  no  mov- 
able parts,  and  the  direction  of  the  car  is  controlled  by  the  carman  throw- 
ing his  car.  If  desired,  latch  or  tongue  points  may  be  used,  operated 


%2»k 

. 

Tread  fe-r  ft 

[ 

''Staple"' 

V 

•10'-  --HJ 

PIG.    375. — SEMIAUTOMATIC   SWITCHES   FOB  MINE   TRACK. 

by  hand  or  by  switches,  which  will  probably  be  necessary  if  the  cars  are 
ran  in  trains.  The  crossover  is  somewhat  intricate  for  the  average  track- 
man to  put  down  correctly,  and  at  times  is  also  troublesome  to  use.  It 
may  be  done  away  with  entirely  with  a  one-car  traffic,  and  a  large  piece  of 
sheet  iron  substituted  as  shown  by  16.  The  inner  rails  are  cut  out  leaving 
only  the  two  outside  rails,  and  if  the  carman  wishes  to  cross  over  he  throws 
his  car  by  a  twist  and  passes  to  the  other  track.  If  he  wishes  to  continue 
on  the  one  track  he  twists  his  car  toward  the  outer  rail.  The  inside  rails 
are  flattened  at  the  end,  curved  outward,  and  screwed  down  to  the  iron 
sheet.  This  open  crossover  may  be  substituted  for  the  three-way  switch, 
doing  away  with  the  guard  rails  and  frogs.  A  single  crossover  is  shown  in 
17;  it  has  but  few  parts,  is  simple,  and  gives  no  trouble.  The  switch 
points  can  either  be  fixed  or  used  as  a  kick  switch. 

Treadle-operated  Switch  (By  A.  H.  Bromly). — Fig.  375  shows  a  switch 
which  can  be  operated  by  the  trammer  as  he  passes  with  his  car  and  before 
the  car  reaches  the  switch  itself.  As  shown,  it  is  applied  to  a  track  with 
18-in.  gage,  the  switch  points  being  24  in.  long.  The  fish  plates  fastening 
the  points  to  the  fixed  rails  have  only  one  bolt  through  the  points  and  are 


TRACK 


459 


left  loose  on  the  point  end  to  permit  the  necessary  play.  The  bridle  con- 
necting the  two  points  is  bolted  to  the  flanges  and  bent  downward  as  seen 
in  the  cross-section.  A  small  strap  is  riveted  to  the  bottom  of  this  so  as 
to  form  a  bearing  for  the  end  of  a  %-in.  round  rod.  This  rod  lies  between 
the  rails  for  about  10  ft.  and  is  held  to  the  ties  by  staples  so  as  to  make  a 
series  of  bearings.  The  end  which  operates  in  the  bridle  of  the  switch 


IT" 

i 

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ii 

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1    i! 

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Hinge 

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j 

#*ft  '" 

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p-*?  Iron- 

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\-' 

A 

t*2t*B 

1 

r 

I 

j  Length 
Fish.PI.  N 

S    'N 

2  Length 
Fish  PI. 

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j*2  Iron- 

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s 

Full. 
•Length 

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ftf 

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Fish  PI. 

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ii. 

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Posh 

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mil  when  not  in  use.  PL  MS 

„,  Hinge 


Latch 


-WT7ff/f""//7l/ 

w/' 


SECTION  A-B 
FIG.    376. — SWINGING   BAIL  CROSSOVER. 


points  is  bent  down  so  as  to  form  a  crank  end.  The  other  end  is  rigidly 
connected  to  a  two- winged  treadle  lying  between  the  rails,  as  shown.  The 
trammer  steps  on  the  proper  wing  of  this  treadle  as  he  approaches  the 
switch  and  the  latter  is  thrown  as  desired.  The  car  will  take  the  same 
side  of  the  switch  as  the  side  of  the  treadle  on  which  the  trammer  steps. 
The  points  should  be  provided  with  iron  straps  to  slide  upon. 


460 


DETAILS  OF  PRACTICAL  MINING 


Temporary  Crossover. — In  surface  or  underground  work,  conditions 
may  exist  where  two  tracks  cross,  without  there  being  any  necessity  for 
switching  from  one  to  the  other.  If  traffic  is  light  or  only  temporary  on 
one  track,  it  is  often  advisable  to  provide  it  with  a  movable  crossover, 
leaving  the  other  track  unbroken.  In  such  case  it  is  brought  through  at  a 
slightly  higher  level  so  that  its  rails  rest  on  the  tops  of  the  permanent 
rails.  These  rails  at  the  crossing  are  hinged  at  one  end  and  latched  at  the 
other  and  can  be  swung  out  when  not  in  use,  thus  leaving  the  lower  track 
unblocked.  The  construction  of  the  hinges  is  shown  in  Fig.  376.  They 
are  held  out  by  half  lengths  of  fish-plates  used  as  fillers,  and  are  themselves 
of  ^2  X  2-in.  iron.  The  latches  are  also  held  out  from  the  fixed  rails  by 
fillers  and  are  of  sufficient  width  to  bear  on  the  head  of  the  rail.  They  are 
°f  M  X  2J^  X  8-in.  iron.  The  inside  of  each  fixed  rail  is  provided  with  a 


.<$'-. 


TURN  SHEET 


•7-6- 


FIG.    377. TURN    SHEET    AND    SWITCH    POINTS    FOR   TURNOUT. 

full-length  fish-plate,  which  holds  the  movable  rail  in  its  proper  position 
when  in  use. 

Turnout  for  Narrow  Drift  (By  Albert  G.  Wolf). — In  Fig.  377 is  shown  a 
cheap  and  simple  turnout,  designed  by  John  B.  Sommers,  foreman  of  the 
Blue  Jay  mine  of  the  Mason  Valley  Mines  Co.  One  rail  is  unbroken  while 
the  other  is  left  open  for  a  space  of  7  ft.  6  in.  and  the  ends  turned  out  for 
about  3  in.  and  pointed.  Two  pieces  of  rail  about  2  ft.  long,  cut  and  bent,  as 
shown,  are  placed  at  the  proper  distance  from  the  points  to  give  the  gage. 
A  clearance  of  1  in.  between  the  ends  of  these  pieces  and  the  through-rail  is 
sufficient  to  allow  the  passage  of  the  wheel  flanges.  An  8  X  4-ft.  turn- 
sheet  is  placed  as  shown,  giving  ample  room  for  a  car  to  sidetrack.  This 
turnout  is  in  use  in  a  narrow  drift  where  the  loaded  and  empty  cars  must 
pass  each  other  in  going  to  and  from  the  shaft.  Its  great  advantage  is 
the  elimination  of  switch  points  and  the  overturned  loads  due  to  them. 
The  loaded  car  follows  the  through-rail,  while  the  empty  is  easily  side- 
tracked, and  the  flaring  ends  of  the  rails  make  it  easy  to  run -the  car  on 
again. 


TRACK 


461 


Cheap  and  Satisfactory  Turntable  (By  L.  O.  Kellogg). — For  trans- 
ferring mine  cars  from  track  to  track,  underground  or  on  the  surface, 
either  a  system  of  switches  or  a  large,  well-leveled  and  well-backed  slick 


f" 19'^' *H 

(Oage) 


PIG.    378. SIMPLE    HOMEMADE    TURNTABLE    FOB    MINE    TRACKS. 

sheet  generally  proves  most  satisfactory.  In  certain  cases,  however,  the 
use  of  a  turntable  is  advisable.  This  is  especially  the  case  where  lack  of 
room  renders  it  necessary  to  make  a  sharp  turn  in  direction.  If  a  turn- 


462  DETAILS  OF  PRACTICAL  MINING 

table  is  to  be  used,  there  is  none  better  than  that  illustrated  in  Fig.  378. 
It  is  a  design  suggested  at  a  Mexican  mine  by  a  mechanic  engaged  on  a 
temporary  .erecting  job.  It  proved  an  excellent  device  in  practice  and  so 
far  as  known,  has  never  been  described  in  print.  It  consists  of  a  fixed 
bottom-plate,  a  movable  upper-plate  and  an  intermediate  spider  carrying 
rollers.  The  relation  of  the  three  pieces  is  maintained  by  means  of  three 
collars  which  nest  together.  As  shown,  the  table  is  applied  to  a  track  of 
0.5 -meter  gage  with  16-lb.  rails;  the  dimensions  are  given  in  English 
units.  The  bottom  plate  is  here  shown  as  made  of  a  J^-in.  iron  casting 
taken  from  the  scrap  heap.  Other  types  of  plates  would  answer,  such  as 
wooden  backing  covered  with  an  iron  sheet  fastened  with  countersunk 
screws.  The  top  plate  is  of  %-in.  steel.  The  spider  has  eight  arms  of 
%-in.  soft  steel  turned  down  at  each  end.  One  end  enters  a  hole  in  the 
J4  X  1-in.  collar  and  is  riveted  over.  The  other  end  carried  a  roller  free 
to  revolve  on  the  turned  portion  and  held  in  by  a  nut.  The  roller  is  of  the 
shape  shown,  a  prolate  spheroid  with  truncated  ends,  to  be  exact.  If  the 
threads  are  bradded  down  a  little,  there  is  no  trouble  experienced  from  the 
nut's  working  off.  The  spider  collar  is  welded  so  as  to  be  continuous. 
The  plate  collars  are  of  bent  angles,  riveted  to  the  plates,  no  attempt  being 
made  to  weld  the  ends.  The  diameter  of  the  collars  is  such  that  the  one 
on  the  upper  plate  fits  loosely  between  that  of  the  spider  outside  and  that 
of  the  lower  plate  inside.  Their  height  is  such  that  the  edges  do  not 
touch  above  or  below  in  any  case,  the  only  contacts  being  those  of  the 
rollers.  The  car  wheels  come  close  enough  to  the  line  of  the  rollers  so  that 
for  a  2400-lb.  load  with  a  J^-in.  steel  plate,  there  was  no  dishing  toward 
the  center,  so  far  as  could  be  seen,  which  would  make  the  collars  bind.  The 
tracks  are  laid  as  bends  over  the  corners  of  the  bottom  plate  and  the  thick- 
ness of  the  rollers  is  determined  by  the  height  of  the  rails,  the  top  of  the 
movable  plate  being  at  such  a  height  as  to  take  the  bottom  of  the  wheel 
flange  as  the  tread  leaves  the  rail.  The  edge  of  the  revolving  plate  is 
made  to  come  just  below  the  inside  edge  of  the  rail  head  at  the  bend.  The 
table  is  cheap  to  put  up;  it  can  be  made  at  any  mine  shop  that  has  a 
lathe.  It  is  reliable  and  durable;  it  can  never  wobble,  as  often  happens 
with  tables  revolving  on  a  central  axis;  it  is  particularly  easy  to  clean, 
since  the  top  plate  can  be  lifted  off  with  one  hand ;  and  it  is  much  simpler 
and  less  expensive  than  the  rather  elaborate  tables  offered  by 
manufacturers. 


XII 
SAFETY  AND  SANITATION 

Hoisting — Collar  Protection — Haulage — Change  Houses — Latrines,  Etc. 
— First  Aid — Miscellaneous 


HOISTING 

Safety  Alarm  for  Slack  Hoisting  Rope. — Devices  are  used  at  the 
Harold  mine  on  the  Mesabi  range  which  will  automatically  signal  the 
engineer,  should  a  hoisting  rope  become  slack.  They  consist  essentially 
of  cradles  of  electric  conductors  stretched  under  the  hoisting  ropes  and 
arranged  to  ring  a  bell  in  the  hoist  room  when  contact  is  made  with  a  rope. 


if-Tower 


Insulated  Copper  Cable-. 


Insulated  Connection 
Timber  Cross-       Copper  Cable  to  Battery 


'ece  ir( 

ii 

T°Wer                                                         Porcelain 
^•Screw  Hook                                    j_a    Insulator 

Insulated  Copper 

Turnbuckle-'' 
Dare  Copper 

Cable 

DETAIL    PLAN  OF  ONE    CONNECTION 

Connection  to 
Battery 

FIG.    379. — ELECTRIC   SIGNAL   ARRANGEMENT  FOR  HOISTING   ROPE. 

The  accompanying  drawing,  Fig.  379,  shows  the  arrangement  diagram- 
matically  and  the  detail  of  one  of  the  four  fastenings.  As  is  general  prac- 
tice on  the  Mesabi,  the  hoist  is  some  distance  from  the  shaft  and  the  ropes 
are  supported  over  this  interval  by  pulleys  on  wood  towers.  Two  insu- 
lated copper  cables  of  twisted  wires  are  stretched  between  two  towers  a 
few  feet  under  each  rope  and  about  18  in.  apart.  The  ends  of  the  cables 
are  held  by  turnbuckles  and  porcelain  insulators.  Several  crosspieces  of 
naked  copper  wire  are  connected  to  the  cables  and  one  cable  is  connected 
through  a  battery  to  the  hoist-room  bell  and  grounded  to  the  main 
steam  pipe.  The  slack  rope  falling  on  the  naked  cross-wires  completes 
the  circuit  through  the  hoist  and  rings  the  bell.  The  hoist  room  being 

463 


464 


DETAILS  OF  PRACTICAL  MINING 


inclosed,  the  engineer  cannot  see  what  is  going  on  at  the  headframe. 
Slack  rope  indicates  trouble  from  two  possible  sources.  The  skip  just 
dumped  may  get  hung  up,  especially  during  freezing  weather  when  ice 
and  snow  will  often  jam  it;  then  when  the  engineer  starts  the  next  trip, 
the  skip  cannot  pull  out  the  rope,  which  becomes  slack  and  rings  the 
warning.  Or  the  skip  may  have  been  hoisted  too  high,  in  which  case 
the  bottom  skip  lands  and  fails  to  pull  out  its  rope  and  the  slack  rope 
rings  the  bell  again.  In  either  case  the  engineer  will  stop  his  engine  and 
investigate. 

Electric  Indicator  for  Hoist  Reverse. — The  Rogers-Brown  Ore  Co., 
Crosby,  Minn.,  is  using  an  electric  device  to  warn  the  hoisting  engineers 


SxlO 
FIG.    380. AUTOMATIC    SAFETY    STOP    FOR    TOP    OF   INCLINE. 

that  the  skip  is  nearing  the  collar  or  has  passed  it.  In  the  words  of  its 
inventor,  J.  P.  Wallheus,  master  mechanic  for  the  mining  company,  the 
device  is  intended  "to  keep  the  engineer's  mind  on  the  reverse  lever  and 
to  warn  him  when  the  skips  are  near  the  dump."  A  60-c.p.  electric  lamp 
is  mounted  on  a  board  in  front  of  the  engineer  and  is  painted  red.  This 
lamp,  reverse  lever  and  indicator  are  connected  to  an  electric  circuit. 
The  circuit  is  open  until  the  skips  are  about  30  ft.  from  the  dump,  at 
which  point  the  circuit  is  closed  by  an  automatic  switch  attached  to  the 
indicator.  This  turns  on  the  red  light,  showing  the  engineer  that  the 
skip  is  near  the  dump.  The  red  light  remains  on  until  the  engine  is 


SAFETY  AND  SANITATION  465 

reversed,  when  the  circuit  is  opened  and  the  red  light  disappears.  For 
the  cage  hoist,  which  does  not  run  in  balance,  the  automatic  drop  switch 
is  on  the  indicator.  This  switch  will  drop  only  when  the  cage  is  hoisted 
a  little  above  the  collar  of  the  shaft,  and  at  this  point  the  red  light  will 
flash  on,  indicating  to  the  engineer  that  he  has  hoisted  too  high  or  that 
he  is  going  in  the  wrong  direction,  as  the  case  may  be. 

Safety  Block  for  Incline  Top. — To  prevent  the  accidental  return  of  a 
car  or  skip  that  has  been  hoisted  to  the  top  of  an  incline  and  detached, 
the  device  shown  in  Fig.  380  is  recommended  by  William  W.  Jones,  state 
mine  inspector,  Albany,  N.  Y.  It  consists  of  two  almost  upright  timbers 
A,  fastened  to  the  square  shaft  D  by  the  straps  C.  The  shaft  is  turned 
in  two  places  to  fit  the  boxes  E.  The  bottoms  of  the  timbers  A  are 
bolted  to  a  transverse  piece  B.  The  hoisted  car  hits  the  timbers  A, 
which  revolve  with  the  shaft,  permitting  the  car  to  pass.  The  weight 
of  B  then  brings  them  to  the  upright  position  and  the  crosspiece  F  pre- 
vents their  swinging  in  the  other  direction.  To  release  the  car,  the  lever, 
which  is  attached  to  a  square  portion  of  the  shaft,  is  used  to  force  the 
timbers  down  below  the  level  of  the  axles.  The  bill  of  material  for  in- 
stalling the  device  on  an  incline  with  a  track  of  3-ft.  gage  is  given  in  the 
table. 

BILL  OF  MATERIALS  FOR  SAFETY  BLOCK;  TRACK  3-rr.  GAGE 

Timber  Iron 

A  2  pieces  6  X  8  in.  by  4  ft.  4  in.  4  bolts  ^  X  20  in. 
B  1  piece  8  X  10  in.  by  2  ft.  2  in.  2  bolts  %  X  14  in. 
F  1  piece  8  X  8  in.  by  5  ft.  2  bolts  %  X  17  in. 

G      2  pieces  8  X  10  in.  by    4  ft.  2  bolts  Y±  X  28  in. 

H  2  pieces  8  X  8  in.  by  3  ft.  2  in.  2  bolts  M  X  34  in. 
I  2  pieces  8  X  8  in.  by  10  ft.  4  bolts  K  X  10  in. 

J       2  pieces  8  X    8  in.  by   5  ft.  2  bolts  Y%  X  18  in. 

K      1  piece    5X    6  in.  by    1  ft.  1  in.     1  shaft  l1^  X  11^6  in.  by  4ft.  4in. 

1  piece  %  X  1^  in.  by  5  ft. 

2  clamps  for  shaft 

2  boxes  2>£  X  8  X  2  in.  bore. 

Car  Catch  at  Incline  Top  (Coal  Age). — A  safety  stop  similar  to  that 
recommended  by  W.  W.  Jones,  is  illustrated  in  Fig.  381.  The  arrange- 
ment needs  little  description.  It  consists  of  a  square  bar,  thrust  through 
a  7-  or  8-ft.  piece  of  scrap  rail  at  a  point  above  the  center  of  gravity  of 
the  latter,  and  with  its  ends  rounded  so  as  to  turn  under  two  clamps  set 
on  timbers,  as  shown.  If  it  is  desired  to  permit  the  return  of  the  cars 
down  the  same  incline,  a  lever  can  be  attached  to  the  end  of  the  bar. 

Light  Safety  Crosshead  (By  Roy  Marcellus). — The  drawing,  Fig. 
382,  shows  a  light  crosshead  used  extensively  in  theCoeur  d'Alene  district, 
Idaho.  It  conforms  with  the  state  laws  regarding  safety  attachments  for 
use  in  sinking.  The  spring  A  is  compressed  when  the  load  is  freely 

30 


466 


DETAILS  OF  PRACTICAL  MINING 


suspended ;  when  tension  is  removed,  as  by  the  ropes  breaking,  the  spring 
extends  and  pulls  the  dogs  E  into  the  face  of  the  guides.     The  drawbar  B 


Kail  in  /'' 

position       Hi?L"7bp  of  Bent 
rests  on 
bent 

FIG.    381. SAFETY    CAR    CATCH    MADE    OP   BAR    AND    RAIL. 


Collar  2" 'O.D.  sk,  S 
I'Thick  ~^ 


Angles 


FIG.    382. STEEL   BUCKET-CROSSHEAD    WITH    SAFETY    DOGS. 

has  a  collar  C  welded  on  it  to  rest  against  the  spring  cup  Z>;  this,  with  the 
nuts  at  the  bottom,  carries  the  load.  The  dogs  are  made  entirely  of 
steel  and  have  teeth  forged  across  their  2-in.  faces.  The  upper  shoes  F 


SAFETY  AND  SANITATION 


467 


are  made  of  angle  iron  riveted  to  the  vertical  angles  G,  having  clearance  in 
the  center  for  the  operation  of  the  dogs;  the  lower  shoes  H  are  made  of 
plate,  as  usual.  The  bucket  is  attached  by  a  chain  to  the  U-bolt  /.  The 
crosshead  can  be  built  as  light  as  300  Ib. 

[It  should  be  noted  that  the  crosshead  must  ride  with  the  bucket,  since 
the  rope  does  not  pass  through,  as  in  the  ordinary  type  of  wooden  cross- 


'        .     .      pipe  filled 
Forked  with  babbitt 

,.  Coiled 


FIG.  383. SAFETY  CROSSHEAD  WITH  AUTOMATIC  RELEASE. 

head.  This  means  that  the  bucket  must  be  swung  from  a  long  chain 
when  sinking,  in  order  to  extend  to  the  shaft  bottom  when  the  crosshead 
is  stopped  at  the  end  of  the  guides.  A  long  connection  such  as  this  means 
considerable  extra  height  in  the  headframe  to  permit  dumping. — EDITOR.] 


468 


DETAILS  OF  PRACTICAL  MINING 


Homemade  Safety  Crosshead  (By  Lowe  Whiting). — The  accom- 
panying drawing,  Fig.  383,  illustrates  a  homemade  crosshead  that  was  used 
in  the  Iron  River  district  of  Michigan,  during  the  sinking  of  a  small  shaft 
to  a  depth  of  450  ft.  A  "  button,"  made  of  a  piece  of  2-in.  pipe,  3  in.  long, 
was  fastened  to  the  rope.  This  was  slipped  over  the  rope  where  the 
strands  had  been  slightly  separated,  a  small  pin  put  through  two  holes  in 
the  pipe  and  through  the  loosened  strands,  and  the  whole  filled  with 
babbitt.  In  descending,  the  crosshead  strikes  the  bumpers  at  the  bottom 
of  the  timbering,  releasing  the  claws,  allowing  the  " button"  to  pass 
between  them  and  the  bucket  to  continue  to  the  bottom  of  the  shaft.  On 
hoisting,  the  button  strikes  the  3-in.  piece  of  hardwood,  lifting  the  cross- 
head,  which  allows  the  coiled  springs  to  again  bring  the  claws  into  action. 

Bucket  Dump -hook. — In  the  Joplin  district  practically  all  the  ore  is 
hoisted  in  buckets.  The  hoisting  engine  is  set  in  a  four-post  derrick 
frame  next  to  the  shaft,  and  the  hoistman  hooks  the  tail,  or  dumping, 


FIG.    384. DUMP-HOOK    USED    ON    JOPLIN   BUCKETS. 

rope  into  the  ring  in  the  bottom  of  the  bucket,  and  slacking  off  on  his 
friction  brake,  dumps  the  bucket.  In  order  to  allow  the  hoistman  to 
grab  this  hook  and  at  the  same  time  to  swing  over  the  door  that  closes  the 
shaft,  this  bucket  hook  is  made  with  a  handle  sticking  out  behind,  as 
shown  in  Fig.  384.  This  handle  should  start  out  from  the  shank  of  the 
hook  about  level  with  the  tip.  This  makes  the  missing  of  a  ring  less 
likely  to  occur,  as  the  hooking  is  then  a  punching  action  directed  so  as 
just  to  miss  ,the  ring  in  the  bucket.  The  advantage  of  the  handle,  no 
matter  where  it  is  put,  is  that  the  point  of  the  hook  is  always  at  a  constant 
distance  above  the  hand,  and  as  all  the  fingers  hold  the  handle  and  none  is 
used  around  the  shank  of  the  hook  there  is  no  danger  of  mashing  the  hand. 
Safety  Bucket  Hooks  (By  F.  C.  Rork). — The  accompanying  drawing, 
Fig.  385,  shows  two  styles  of  bucket  hooks  which  are  quite  common  in 
Canadian  mines.  They  comply  with  the  Ontario  laws,  which  specify 
that  no  open  hook  shall  be  used  in  hoisting  or  lowering.  The  hooks  can 


SAFETY  AND  SANITATION 


469 


be  made  by  any  blacksmith  from  material  which  is  usually  kept  in  stock 
at  a  mine  and  combine  safety  with  ease  and  speed  of  operation. 


FIG.  385. BUCKET  HOOKS  COMPLYING  WITH  ONTARIO  LAW. 

Sliding  Chain  Gates  on  Cage  (By  F.  H.  Armstrong). — For  a  safe  yet 
easily  handled  gate  for  a  cage,  bars  of  %-in.  pipe  fastened  to  two  chains 
are  used,  as  shown  in  Fig.  386.  The  chains  run  over  pulleys  set  at  the 


Gate  Open 

£j~»™~~™o~^ 

Lead     ¥ 
Weight 

/ 
Top        of  /    Sheet 

Iron     X   Sides 

l^/i 
;   /& 

tJjX      ^  Floor  of  Cage 

J       \ 

i               Lead  \\ 

FIG.    386.— CAGE    GATES    OF   CHAIN   AND   PIPE. 

corners  of  a  triangle.     On  the  hypotenuse  of  the  triangle  is  a  lead  counter- 
balance to  offset  the  weight  of  the  bars.     When  the  gate  is  open,  the  bars 


470 


DETAILS  OF  PRACTICAL  MINING 


are  on  the  horizontal  part  of  the  chain  along  the  roof  of  the  cage  and  the 
weight  is  near  the  bottom  of  the  cage.  When  the  bars  are  down  —  gate 
closed  —  the  weight  is  near  the  top  of  the  cage.  This  appliance  is  simple, 
reliable  and  easily  operated. 


COLLAR  PROTECTION 

Lifting  Guards  for  Shaft  Collar.  —  In  the  lead  district  of  southeastern 
Missouri,  the  ore  lies  directly  on  top  of  a  water-bearing  sandstone  in 
which  deep  sumps  are  not  desirable  owing  to  the  difficulty  in  handling 
the  water.  Due  to  the  shallow  sumps  it  is  not  possible  to  use  cages  having 
more  than  one  deck.  Thus  in  order  to  handle  the  production  of  the  mine, 
relatively  high  hoisting  speed  must  be  used  and  all  unnecessary  delays 


ri? 


FIG.    387. LIFTING    RAILING    FOR    SHAFT.  FIG.    388. PLATFORM  SHAFT  COVER. 

in  putting  the  cars  on  and  off  at  the  surface  avoided.  This  fact  is  made 
clear  when  it  is  known  that  as  much  as  400  to  500  tons  are  regularly 
hoisted  in  eight  hours  from  a  depth  of  approximately  450  ft.  on  a  one-deck 
cage  using  1-ton  cars,  and  that  often  as  much  as  800  tons  are  handled  at 
some  shafts  using  1^-ton  cars.  This  necessity  for  cutting  down  delays 
has  developed  several  types  of  automatic  guards  for  shaft  collars  which 
are  operated  by  the  cage  itself.  Such  a  guard,  whether  it  be  a  railing 
or  a  platform,  must  be  made  as  light  as  consistent  with  strength  in 
order  to  diminish  the  shock  when  it  is  picked  up  by  the  cage.  A  common 
form  of  platform  consists  of  1  X  4-in.  planks,  made  up  as  shown  in  Fig. 
388.  At  the  Desloge  Consolidated  shafts,  a  lifting  guard  railing  or  frame 
is  used ;  it  is  no  heavier  than  the  platform  and  is  regarded  as  much  safer. 
The  construction  of  this  frame  is  shown  in  Fig.  387.  The  lower  braces 
are  notched  clear  into  the  corner  posts,  while  the  upper  ones  are  notched 


SAFETY  AND  SANITATION 


471 


in  only  about  half  way.  A  J^-in.  steel  truss  rod  is  used  to  distribute 
properly  the  stress  due  to  the  sudden  lifting  of  the  frame.  This  rod 
passes  through  loops  in  the  straps  by  which  it  is  fastened  to  the  top  cross- 
pieces  of  the  framework.  The  corner  posts  are  placed  at  an  angle  to 
give  added  strength  as  well  as  to  decrease  the  weight  of  the  top  of  the 
structure.  Rubber  bumpers  are  used  to  take  up  the  jar  of  the  frame  when 
it  drops  back  upon  the  landing  floor. 

Safety  Bonnet  for  Shaft  Opening  (By  E.  H.  Edyvean).— Fig.  389 
shows  a  safety  guard  or  bonnet  protecting  the  cage  compartment  of  the 


5  "Channel  Div/der--'' 

NOTE    f  Plan 

Alt 'angles  5x$xk.'f 
except  a6  specified 


Hardwood 
dfock.. 


Half  End  Elevation  Half  Cross-Section 

FIG.    389. SHAFT    COVER    OPERATED    BY    CAGE.. 

shaft  at  the  Bristol  mine,  Crystal  Falls,  Mich.  It  is  in  use  at  a  point 
in  the  shaft  house,  some  distance  above  the  surface,  where  the  waste 
rock  is  landed  after  hoisting  in  the  cage.  The  bonnet  is  constructed  of 
steel  with  a  hardwood  lining  for  the  top  opening.  The  3  X  3  X  M~m- 
end  angles  are  extended  6  in.  outside  the  body  of  the  bonnet  and  serve 


472 


DETAILS  OF  PRACTICAL  MINING 


as  the  means  of  support.  These  ends  are  reinforced  with  corner  brackets 
as  shown  in  the  drawing.  The  sloping  sides  are  made  of  J^-in.  steel 
plate,  reinforced  with  3  X  3  X  M-in.  angles.  The  opening  between  the 
plates  gives  plenty  of  room  for  the  lever  operating  the  safety  catches  on 
the  cage.  The  shoes  are  of  the  same  gage  and  move  on  the  same  guide 
as  those  on  the  cage.  The  wood  lining  in  the  top  opening  protects  the 
top  frame  from  the  hoisting  rope.  The  bonnet  is  held  over  the  shaft  by 
four  supports,  one  on  each  corner.  These  consist  of  J^-in.  steel  plates 
securely  riveted  to  the  dividers,  and  of  hardwood  blocks  bolted  to  the 
plates;  the  blocks  are  easy  to  replace  in  case  they  are  broken.  The 
yoke  of  the  ascending  cage  catches  the  bonnet,  raises  it  and  supports  it 
while  the  cage  is  at  the  landing.  When  the  cage  descends,  the  bonnet 
drops  on  its  supports  and  closes  the  shaft  opening  almost  entirely,  thus 
serving  as  a  simple  and  effective  safety  device. 


fbs/fton  ofqafe 

when  folded    '• 


FIG.    390. SHAFT-COLLAR   GATE    OF   WOOD   AND   IRON  BARS,    ARRANGED 

TO   FOLD. 

Folding  Gate  across  Shaft  (By  W.  H.  Jobe). — The  accompanying 
illustration,  Fig.  390,  represents  a  shaft  gate  designed  by  Capt.  Edward 
Jacka,  of  the  Armenia  mine,  Crystal  Falls,  Mich.  It  consists  of  two 
horizontal  wooden  bars,  the  top  one  2  X  4  in.,  the  lower  2  X  2  in.  These 
are  connected  by  eight  vertical  iron  bars  bolted  loosely  at  the  top  and 
bottom.  The  upper  horizontal  bar  pivots  on  a  J^-in.  bolt,  turning  in  a 
2<4-in.  pipe  in  the  shaft  timber.  The  lower  horizontal  bar  ends  in  an  iron 
strap  turned  at  right  angles,  %  in.  thick  with  a  %-in.  slot  along  its  middle. 
A  }/£-in.  bolt  through  the  slot  holds  the  strap  to  the  shaft  timbers,  but 
permits  it  to  slide.  Thus,  as  the  gate  is  raised,  it  folds  up  as  shown. 
A  counterweight  of  four  2  X  2-in.  iron  bars  is  bolted  to  the  upper  hori- 
zontal bar.  One  of  the  vertical  bars  has  two  offsets  as  shown,  and  serves 
as  a  handle. 

Hinged  Shaft  Bar. — The  2  X  6-in.  wooden  bar  across  the  man-cage 
compartment  at  the  Zenith  mine,  Ely,  Minn.,  is  hinged  in  the  middle. 


SAFETY  AND  SANITATION 


473 


This  permits  it  to  be  lifted  and  lowered  somewhat  more  quickly,  makes 
it  less  likely  to  fall  accidentally  when  standing  open  .and  requires  less 
headroom  to  accommodate  it.  The  manner  in  which  it  is  pivoted  and 
supported  is  shown  in  Fig.  391.  The  hinge  is  bolted  to  the  lower  side, 
so  that  by  placing  the  hand  under  the  bar  at  the  point  A,  the  bar  can  be 
lifted  with  one  motion.  The  hinge  is  made  in  the  shop  and  is  unusually 
stout.  The  ends  of  the  bar  are  run  through  vertically  with  J^-in.  bolts 


FIG.    391. BAR   ACROSS    MAN  WAY    COMPARTMENT. 

as  a  precaution  against  splitting  and  the  loose  end  has  an  iron  wearing 
plate  underneath. 

Swinging  Shaft  Gate  of  Iron  (By  W.  H.  Jobe). — A  shaft  gate  used 
by  the  Verona  Mining  Co.  of  Michigan  is  shown  in  Fig.  392.  It  consists 
of  a  frame  of  pipe  and  iron  fence  fittings  braced  with  strap  iron.  The 
gate  is  hung  at  a  slight  inclination,  so  as  to  swing  shut  of  its  own  weight. 
An  iron  plate,  %  X  6  in.,  is  fastened  to  straps  from  the  gate  at  the  bottom 
and  serves  as  a  "toe  board." 


Collar  of  Sharff- 

PIG.    392. GATE  OF  PIPE  AND  STRAP  IRON,   SWINGING  SHUT  BY  GRAVITY. 

Handy  Gate  Latch. — The  gate  latch  illustrated  in  Fig.  393  is  one  used 
at  the  Bennett  mine,  Keewatin,  Minn.  While  in  this  particular  instance 
it  was  applied  to  the  gate  into  the  manway,  through  the  fence  around  the 
shaft  collar,  it  is  suitable  for  any  gate  and  is  extremely  neat,  reliable  and 
convenient.  It  consists  of  a  horizontal  finger  attached  to  the  gate  and  a 
ring  held  loose  in  a  double-strap  hanger  fastened  to  a  corner  post  of  the 
fence.  The  2J^-in.  ring  rests  on  a  J^-in.  rivet  between  the  two  straps. 


474 


DETAILS  OF  PRACTICAL  MINING 


In  closing  the  gate  the  finger  strikes  the  ring,  which  is  so  positioned  as 
to  move  freely  inward  and  upward  and  allow  the  finger  to  pass.  The 
gate  cannot  open  by  itself,  as  the  finger  strikes  above  the  center  of  the 
ring  so  that  the  latter  cannot  lift;  nor  can  it  swing  outward,  since  it 
strikes  the  closed  end  of  the  double  strap;  the  latch  is  released  by  lifting 
the  ring  with  the  hand. 

Protective  Combing  for  Manway  Top. — Cribbed  manways  are  raised 
through  vertically  from  level  to  level  in  the  mines  at  Ely,  Minn.,  operated 
by  the  Oliver  company.  The  tops  of  these  are  covered  with  planks  spiked 
to  the  cribbing  and  a  rather  small  opening  is  left  around  the  ladder.  In 
order  that  material  may  not  accidentally  be  kicked  down  the  manway  by 
anybody  approaching  its  top,  a  low  railing  or  combing  is  nailed  around  the 
opening.  This  is  of  2  X  6-in.  material,  constructed  in  the  manner  shown 


6*8  Corner  pos  t  of 
railing 


FIG.    393. RING    AND    FINGER   LATCH    ON    SHAFT    GATE. 

in  Fig.  394.  It  was  found  that  the  opening  at  the  manway  top,  while 
large  enough  to  permit  the  passage  of  a  man,  made  handling  of  the  Draeger 
resuscitation  apparatus  difficult,  if  circumstances  should  compel  it  to  be 
taken  into  the  stopes.  To  get  more  room,  therefore,  another  board  on  the 
side  of  the  opening  opposite  the  ladder  was  cut  away  and  fitted  with 
hinges,  so  that  it  could  be  thrown  back  when  necessary,  although  usually 
kept  closed.  The  dimensions  and  arrangement  of  the  opening,  combing, 
etc.,  are  somewhat  different  in  different  manways,  but  the  illustration 
shows  a  typical  case. 

Safety  Door  for  Chute  Top  (By  H.  H.  Hodgkinson).— Underground 
trammers  will  persist  in  leaving  open  the  doors  over  ore  chutes,  exposing 
others  to  the  danger  of  falling  in,  if  the  chutes  are  in  the  main  traveling 
roads.  Such  chutes  should  always  be  provided  with  doors-,  and  they 


SAFETY  AND  SANITATION 


475 


should  be  closed  when  not  in  use.     A  piece  of  J^-in.  plate  22  X  42  in.  will 
make  a  handy  door  for  a  chute  between  the  rails  when  a  2-ft.  gage  track 


Raise  Cribbing 


SECTION 

PIG.    394. MANNER   OP   PROTECTING    RAISE    TOPS. 


PIG.    395. CHUTE    COVER   OPENED   AND   CLOSED   WITH   ONE   ROPE. 

is  used.     A  piece  of  %-in,  hemp  rope  about  18  ft.  long  and  two  small 
pulleys  will  not  only  save  time  and  make  it  easier  for  the  men  pushing  the 


476  DETAILS  OF  PRACTICAL  MINING 

cars  to  open  and  close  the  doors,  but  will  help  them  to  remember  that  they 
must  do  it.  The  arrangement  is  shown  in  Fig.  395.  By  pulling  the  rope 
at  P  with  a  quick  jerk,  the  door  will  swing  all  the  way  back  and  rest  on  the 
platform,  and  when  in  the  latter  position  another  jerk  at  the  rope  will 
close  it.  The  pulley  A  is  directly  over  the  hinges  of  the  door  and  is  fast- 
ened to  the  cap  of  a  timber.  The  pulley  B  is  also  fastened  to  a  cap  about 
12  ft.  from  A  directly  over  the  center  of  the  track.  The  rope  at  P  hangs 
down  in  the  center  of  the  track  and  is  low  enough  to  touch  the  trammers 
on  the  shoulder.  The  rope  should  always  be  extended  far  enough  along 
the  drift  to  enable  the  trammers  to  open  the  door  just  before  they  reach 
the  dump,  thus  avoiding  delay. 

HAULAGE 

Automatic  Gong  for  Underground  Motor. — The  excellent  safety 
device  illustrated  in  Figs.  396  and  397  consists  of  a  gong  so  attached  to  the 
wheel  of  an  underground  electric  locomotive  as  to  ring  whenever  the  wheel 
revolves,  and  thus  automatically  signal  the  motor's  approach  to  anybody 
in  the  haulageway.  The  gong  in  the  form  illustrated  was  developed  at  the 
Oliver  mines  at  Ely  on  the  Vermilion  iron  range  after  a  good  deal  of  experi- 
menting. The  first  type  of  gong  used  for  the  purpose  involved  a  spring 
and  trigger  arrangement  which  required  constant  attention  and  repair. 
In  the  effort  to  avoid  this  difficulty  the  scheme  to  be  described  was  hit 
upon. 

The  gong  is  attached  to  the  center  of  the  wheel  on  the  outside,  as  shown 
in  Fig.  397.  The  details  of  construction  are  exhibited  in  Fig.  396.  A 
IJ^-in.  piece  of  round  iron  is  turned  down  at  each  end  to  form  two  shoul- 
ders and  one  turned  portion  is  threaded.  This  is  slipped  through  the  hole 
in  the  center  of  the  10-in.  gong  and  fastened  to  it  with  a  nut.  The  other 
end  is  riveted  to  an  iron  plate,  10  in.  in  diameter  to  correspond  to  the  gong 
and  about  %  in.  thick.  The  length  of  the  pin  is  such  that  the  plate  clears 
the  gong  about  %  in.  A  piece  of  flat  iron  is  wrapped  partly  around  the 
pin  and  its  ends  shaped  to  correspond  roughly  to  the  inside  of  the  gong. 
This  is  riveted  through  the  pin  and  the  ends  are  also  riveted  together, 
forming  a  paddle.  An  iron  or  steel  ball  about  an  inch  in  diameter  com- 
pletes the  device.  The  plate  is  fastened  to  the  wheel  with  two  bolts,  not 
shown  in  the  illustration.  The  gong,  plate,  pin  and  paddle  revolve  with 
the  wheel,  the  ball  being  the  only  loose  part.  The  paddle  catches  the 
ball  and  lifts  it  to  a  point  near  the  top,  when  it  rolls  down  the  paddle  and 
drops  from  the  pin,  striking  the  lower  edge  of  the  gong  and  ringing  it. 
The  device  seems  perfect  except  in  one  respect:  At  55  to  60  r.p.m., 
centrifugal  force  is  sufficient  to  overcome  the  force  of  gravity  and  the 
gong  revolving  at  that  speed  will  not  ring.  With  the  28-in.  wheel  used  on 


SAFETY  AND  SANITATION 


477 


the  motor,  this  corresponds  to  about  5  miles  per  hour.  The  company's 
mechanical  department  has  expended  considerable  ingenuity  in  the  at- 
tempt to  overcome  this  defect  and  has  tried  various  devices.  One  of 
these  worked  successfully  at  high  speeds,  but  failed  at  low  speeds  and 
furthermore  was  so  complicated  as  to  destroy  the  chief  merit  of  the  device, 
its  simplicity  and  strength.  Five  miles  per  hour,  it  should  be  noted,  is 
fast  enough  for  underground  tramming  under  most  conditions.  The 
design  shown  is  that  used  where  the  wheels  are  outside  the  motor 
casing.  When  the  wheels  are  inside  the  casing  is  pierced  at  a  point 


"•-  Plate  for  attachment 
to  wheel 

SECTION  A-A,  INCLUDING  PLATE 
FIG.    396. — DETAILS   OF   GONG. 


FI6.2 


FIG.    397. — GONG  ATTACHED 
TO  WHEEL. 


corresponding  to  the  center  of  the  wheel  and  the  pin  of  the  gong  extended 
through  the  hole  and  into  the  wheel  center  as  a  bolt,  the  device  thus  re- 
volving on  the  outside  of  the  casing. 

Hanging  Troughs  for  Protecting  Trolley  Wires  (By  Claude  T.  Rice). — 
To  guard  against  the  danger  of  electric  shock  from  underground  trolley 
wires  some  form  of  protection  is  necessary.  This  usually  takes  the  form 
of  a  trough,  the  sides  of  which  extend  down  below  the  wire  and  keep  men 
from  hitting  the  wire  with  their  bodies  or  with  tools  they  may  be  carrying 
on  their  backs.  At  chutes  the  danger  is  especially  great,  but  it  costs 
little  more  and  makes  the  workings  far  safer,  to  extend  the  trough 
protection  throughout  the  mine. 

Different  methods  for  supporting  the  protecting  trough  have  been 


478 


DETAILS  OF  PRACTICAL  MINING 


suggested.  Probably  the  cheapest  is  a  modification  of  the  system  used  to 
carry  the  insulators  at  the  Mascotte  tunnel,  Bingham,  Utah.  Here  stop- 
ing  drills  put  two  inclined  holes  into  the  adit  roof,  12  in.  deep  and  2J^  in. 
in  diameter;  4  X  4-in.  pegs  sharpened  to  fit  are  driven  into  the  holes.  As 
these  two  pegs  slope  away  from  each  other,  the  trolley  trough  would  be 
securely  held  to  the  roof  if  it  were  nailed  directly  to  their  squared  heads,  as 
shown  in  Fig.  398,  1.  This  method  is  practicable  when  the  roof  is  of 
uniform  height,  so  that  long  plugs  are  not  necessary  to  keep  the  trolley 
board  approximately  level. 


0 

0 

© 

© 

0 

0 

Plate  A 


Form  B 


FIG.    398. FORMS    OF  TROLLEY    TROUGH   HANGERS. 

A  better  method,  adaptable  to  all  roofs,  is  that  used  at  some  of  the 
mines  of  the  Cleveland-Cliffs  Iron  Co.  in  the  Lake  Superior  district.  Here 
steel  pins  are  fastened  in  vertical  holes  by  a  wedge  driven  into  the  split 
inner  end  of  the  pin,  as  seen  in  2.  The  outer  end  of  the  pin  is  also  split 
and  bent  out  to  form  wings.  These  wings  are  flattened  and  to  them  is 
riveted  a  J^-in.  plate  carrying  four  holes  through  which  J^-in.  carriage 
bolts  pass  and  support  the  straps  carrying  the  protecting  trough.  The 
plate  is  made  wide  enough  for  four  bolts,  to  allow  splicing  the  troughs 
at  the  pins.  It  is  just  as  well,  however,  to  splice  the  troughs  with  top  or 
side  cleats  and  so  have  the  wings  carry  the  straps  directly  without  the 


SAFETY  AND  SANITATION  479 

intervening  plate.  This  makes  a  strong  hanger  where  the  trough  has  to 
be  carried  at  some  distance  from  the  roof,  and  it  is  a  good  way  to  use  up 
old  drill  steel.  At  the  Cliff  shaft  of  the  Cleveland-Cliffs  company  a  some- 
what less  expensive  hanger  was  devised  by  Lucien  Eaton,  superintendent 
of  the  Ishpeming  mines  of  the  company.  Pieces  of  IJ^-in.  pipe  are  fast- 
ened by  wooden  wedges  in  holes  in  the  roof  10  in.  deep  as  shown  in  3. 
The  outer  end  of  the  pipe  is  split,  one  cut  following  the  weld.  This  end  is 
then  spread  out  and  the  wings  flattened  on  forms.  The  first  form  A  consists 
of  a  flat  piece  of  iron  1  in.  thick,  4  in.  wide  and  6J^  in.  long.  A  pin  at  the 
center  of  the  form  projects  both  top  and  bottom;  the  top  end  enters  and 
centers  the  pipe,  while  the  bottom  end  is  shaped  to  enter  the  hardie  hole 
of  the  anvil  and  hold  the  form.  The  wings  of  the  pipe  having  been  bent 
down  and  flattened  are  bent  at  right  angles  over  the  ends  of  the  form. 
The  pipe  with  the  wings  still  hot  is  now  completed  on  the  second  form  B. 
This  is  merely  a  2  X  2-in.  bar  of  iron  with  its  end  bent  down  and  shaped  to 
enter  the  hardie  hole.  On  this  form  another  right-angle  bend,  back 
toward  the  center  of  the  hanger,  is  made  in  each  wing.  In  this  way  a 
6/4  X  2-in.  yoke  is  formed  to  receive  the  top  board  of  the  trolley  trough. 
The  yoke  is  bored  for  two  J^-in.  bolts,  one  on  each  side,  by  which  the 
2  X  6-in.  trolley  boards  are  securely  fastened.  With  this  system  the 
trolley  boards  are  spliced  by  the  side  boards  of  the  trough  or  by  a  top 
cleat.  By  the  use  of  forms  a  uniform  size  and  shape  of  hanger  is  insured 
and  much  time  is  saved  in  the  blacksmith  shop.  A  good  blacksmith  can 
easily  make  10  hangers  per  hour.  As  all  scrap  pipe  and  short  lengths 
that  are  in  a  fair  condition  can  be  utilized,  the  hangers  are  relatively  cheap 
and,  unless  unduly  long,  are  quite  strong  enough.  Measurements  are 
taken  at  the  different  points  along  the  drift  and  the  hangers,  properly 
numbered,  are  made  and  sent  down  ready  to  be  put  10  in.  into  the  plug 
holes  and  yet  bring  the  trolley  board  level,  so  that  the  trolley  will  run  at 
approximately  the  same  height  throughout  the  mine,  which  is  desirable 
for  the  best  operation.  Aside  from  the  advantage  derived  from  the  use 
of  the  protecting  troughs  from  the  standpoint  of  safety  the  top  board  of 
the  trough  acts  as  a  guide  to  the  trolley  pole  should  it  jump  the  wire,  and 
thus  saves  it  from  injury.  The  Cleveland-Cliffs  company,  while  it  does 
not  use  a  trough  along  the  entire  line,  does  use  a  top  board,  to  carry  the 
insulators.  Troughs  are  used  only  where  there  is  much  travel,  and  near 
chutes. 

V-shaped  Trough  for  Trolley  Wire  (By  Allen  H.  Foster). — Supple- 
mentary to  the  article  by  Claude  T.  Rice,  the  accompanying  illustration, 
Fig.  399,  shows  a  trough  which  is  useful  where  there  is  little  headroom 
available.  The  stringer  boards  A  are  1-  or  2-in.  planks,  depending  on  the 
span  between  supporting  plugs.  Blocks  B  are  placed  at  the  points  where 
trolley  ears  are  located,  and  wherever  it  is  thought  desirable  to  stiffen  the 


480 


DETAILS  OF  PRACTICAL  MINING 


trough.  Under  comparatively  dry  Conditions  the  petticoat  insulator  S 
can  be  omitted  and  the  ear  attached  directly  to  the  block  B.  In  this  case 
the  blocks  should  be  treated  with  an  insulating  compound. 


PIG.    399. INVERTED-V    TROLLEY-WIRE     PROTECTING    TROUGH. 


Timber 


*   Strews* 


Trolley-. 
Ear 


f  x^.  Iron- 
Trolley  Ea> 


FIG.    400. DOUBLE     HANGER     SUS- 
PENDED   FROM    ROOF. 


FIG.    401. DOUBLE   HANGER  SUS- 
PENDED   FROM   TIMBERS. 


_  ^  COAL  A6E 
FIG.    402. — SINGLE  INDEPENDENT  HANGERS  DRIVEN  INTO  ROOF. 

Trolley-wire  Troughs  for  Uniform  Height  of  Back  (Coal  Age). — A 
method  of  suspending  troughs  for  trolley  wires,  where  it  is  not  necessary 


SAFETY  AND  SANITATION 


481 


to  allow  for  serious  inequalities  in  the  height  of  the  back,  is  shown  in  Figs. 

400,  401  and  402.     An  iron  strap  is  held  by  each  trolley  hanger,  and  boards 
are  bolted  to  these.     If  cut  to  length,  they  can  be  notched  and  joined  at 
the  hangers,  as  shown  in  Fig.  400.     They  should  be  wide  enough  and 
placed  low  enough  to  cover  the  point  of  greatest  sag  in  the  wire.     Methods 
of  attachment  to  rock  roofs  and  to  timbers  are  shown  in  Figs.  400  and 

401,  respectively.     If  the  trolley  hangers  are  spaced  more  than  15  ft. 
apart,  intermediate  straps  should  be  provided  for  the  boards.     In  case 
it  is  desirable  to  carry  the  protection  independently  of  the  trolley-wire 
supports,  the  method  shown  in  Fig.  402  is  available.     In  this  case  the 
boards  are  merely  lapped  in  the  bracket  and  no  bolting  is  necessary. 

Trolley-wire  Protection  of  Round  Lagging  (By  W.  H.  Jobe). — The 
accompanying  illustration,  Fig.  403,  represents  a  method  of  protecting 
underground  trolley  wires,  devised  by  Capt.  E.  Carlson,  of  the  Bristol 


Section  Along  Drift 


/'  Qreer?  Lagging 
Trolley  Wire 

Section  Across 

Drtft  y 

Chute 


Post 

FIG.    403. — POLE   GUARDS  TO    PREVENT  CONTACT   WITH  TROLLEY   WIRE. 


mine,  near  Crystal  Falls,  Mich.  Lengths  of  round  green  tamarack  lag- 
ging are  notched  and  spiked  to  the  drift  caps  on  both  sides  of  the  trolley 
wire.  This  material  is  readily  had  and  is  cheap.  It  is  more  easily  placed 
than  the  ordinary  inverted  trough  and  is  much  stronger  and  capable  of 
resisting  the  shock  of  blasting  in  the  chutes,  which  is  frequently  necessary. 
Safety  Hand  Grip  for  Car  (By  H.  H.  Hodgkinson). — When  ore  cars 
are  heaped  full,  the  trammers  often  receive  badly  bruised  hands  from 
the  chunks  on  the  tops  striking  chutes  and  rolling  down,  inasmuch  as 
the  men  persist  in  gripping  the  angle  iron  around  the  rim  of  the  car 
body.  It  is  sometimes  necessary,  also,  to  hold  back  the  car,  in 
order  to  stop  it  or  to  prevent  it  from  going  down-grade  too  fast.  There 
is  no  suitable  place  on  the  car  for  holding,  and  the  angle-iron  rim 
gives  a  poor  grip.  The  convenience  illustrated  in  Fig.  404  consists 
of  a  piece  of  IJ^-in.  pipe  threaded  at  each  end  and  attached  to  the  car 
by  means  of  two  4X3  Xj^-in.  angle  irons,  which  have  each  a  1^-in. 
hole  bored  to  fit  the  outside  of  the  pipe.  These  two  angle  irons  are  riveted 
fast  to  the  body  of  the  car  in  such  a  position  as  to  bring  the  grip  just 
under  the  angle-iron  rim,  which  will  then  act  as  a  guard  to  the  hands 

31 


482 


DETAILS  OF  PRACTICAL  MINING 


of  the  trammers.     A  IJ^-in.   pipe  coupling  is  cut  in  half  to  take  the 
place  of  a  nut,  half  being  put  on  each  end  of  the  pipe  or  grip. 

. »  .if 

^ni       --/^  Wroughf-lron  Pipe        [p1  1$  Pipe  collar 
P[  ID*  cut     in  half 


I  t       I  ^ 

4x3x£?~* 


j "Rivets 

FIG.    404. A   PIPE-BAR   GRIP   FOR  MINE   CARS. 

Shoeing  Mean  Mules. — Trouble  is  often  experienced  in  shoeing  mules, 
especially  underground.     In  Fig.  405  are  shown  the  features  of  a  shoeing 


^^^^^^ 

Side  Elevation  of  Stall 
FIG.    405.  —  STALL   FOR   SHOEING   REFRACTORY   MULES. 


stall  at  one  of  the  shafts  of  the  St.  Louis  Smelting  &  Refining  Co.,  in  the 
Flat  River  district  of  southeastern  Missouri.     This  stall  is  made  narrow 


SAFETY  AND  SANITATION  483 

so  that  the  mule  has  not  much  lateral  leeway.  There  is  a  pipe  A  at  the 
manger  or  head  end  of  the  stall  against  which  the  breast  of  the  mule 
comes.  This  is  put  in  after  the  mule  has  been  forced  back  against  the 
other  pipes  and  the  board  that  are  used  to  restrain  him.  By  this  breast 
pipe  he  is  kept  from  moving  forward ;  by  the  board  B  that  is  put  over  his 
back  he  is  kept  from  rising  to  kick;  by  the  pipe  (7,  which  is  put  in  at  the 
same  height  as  the  breast  pipe,  he  is  kept  from  backing  out  of  the  stall; 
and  by  the  pipe  Z>,  which  is  wrapped  with  old  gunny  sacks  to  prevent  him 
from  injuring  himself,  he  is  prevented  from  kicking.  The  foot  that  is  to 
be  shod  is  raised  up  over  the  pipe  Z),  which  is  held  in  iron  straps  F,  bolted 
to  the  back  posts  of  the  stall,  and  then  is  tied  down  by  the  rope  E  which 
is  fastened  to  the  cleat  G.  By  this  rope  the  mule  is  prevented  from  jerk- 
ing his  foot  back  out  of  the  shoer's  grasp.  The  mule  can  be  turned 
around  and  his  front  feet  also  shod  in  this  stall  if  he  causes  trouble  by  not 
standing  still  or  by  trying  to  strike  the  man.  Some  mules  give  trouble  by 
laying  their  weight  on  the  man.  This  can  be  remedied  by  rigging  up  a 
swing  and  putting  a  band  or  surcingle  around  the  mule  and  swinging  him 
so  as  to  take  his  weight  off  the  shoer. 

CHANGE  HOUSES 

New  Type  of  Copper  Queen  Change  House. — Prior  to  1913,  the 
change  houses  or  drys  for  miners  of  the  Copper  Queen  Consolidated 
Mining  Co.  in  Bisbee,  Ariz.,  were  all  of  one  type,  similar  in  equipment 
and  construction  to  others  in  the  Southwest.  They  were  usually  two- 
story  wooden  buildings,  with  corrugated-iron  roofs  and  walls.  They  had 
wash  rooms  and  shower  baths,  and  lockers  for  clothing.  The  lockers  were 
ventilated  and  had  steam  pipes  beneath.  Each  change  house  had  its  own 
heating  plant  for  warming  the  building  and  heating  water.  Exhaust 
steam  was  not  available,  as  all  power  was  generated  at  a  central  station 
and  distributed  by  electricity  or  compressed  air.  When  new  buildings 
were  designed,  an  attempt  was  made  to  improve  on  the  older  construction, 
particularly  in  the  directions  of  sanitation  and  reduction  of  maintenance 
costs.  In  the  old  buildings,  the  wooden  floors  wore  rapidly,  and  gradu- 
ally became  saturated  with  wash  water,  etc.  Although  the  lockers  were 
ventilated  at  top  and  bottom,  wet  clothes  were  packed  too  closely  to  allow 
free  circulation  of  air.  It  was  necessary  to  keep  the  rooms  uncomfortably 
hot  in  order  that  the  clothes  might  be  dried.  The  Uncle  Sam  change 
room  was  built  in  the  winter  of  1912-13.  It  was  followed  by  one  at  the 
West  Atlanta  shaft  and  later  by  a  larger  building  at  the  Sacramento 
shaft.  These  are  all  single-story  buildings,  with  cement  floors.  Small 
lockers  are  used  for  such  articles  as  might  be  lost  or  stolen,  but  all  cloth- 
ing is  hung  from  the  ceiling.  The  wet  clothes  are  thus  spread  out  to 


484 


DETAILS  OF  PRACTICAL  MINING 


favor  drying  by  free  ventilation,  rather  than  by  the  heat  of  steam  pipes. 
Each  change  room  has  a  washroom  and  shower  baths,  accommodations 
for  foreman,  bosses  and  timekeeper,  and  a  small  storeroom. 

For  one  end  of  the  Sacramento  building  a  cut  in  the  ground  was  neces- 
sary, while  the  other  was  built  on  fill.  The  building  was  surrounded  by 
shallow  concrete  foundation  walls  and  the  fill  was  settled  by  water.  The 
cement  floor  was  laid  on  the  ground,  with  the  exception  of  the  wash  room, 
which  was  supported  by  iron  posts  and  laid  on  Berger  plate.  The  skele- 
ton of  the  building  is  of  timber,  plastered  within  and  without  on  Hy-rib. 
Fig.  406  is  a  plan  of  the  change  house.  The  heating  plant,  separated 


fl 


-  Drain  c 
M ^.,.v m..«._^.  _.;../a*!r* _ 


= 


. 

c'  -^ 

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PIG.    406. ARRANGEMENTS    OF    A    COPPER    QUEEN    CHANGE   HOUSE    OF    THE    DESIGN 

RECENTLY   ADOPTED. 

from  the  change  room  to  cut  down  the  fire  risk,  is  situated  below  the 
building,  so  that  condensed  water  drains  back  to  the  boiler.  The  heater 
is  an  " Ideal"  steam  boiler  of  the  American  Radiator  Co.,  36-9  section. 
For  heating  the  main  room  650  sq.  ft.  of  radiating  surface  is  provided,  and 
70  more  for  the  office  and  the  bosses'  change  room.  The  steam  pipes  are 
laid  around  the  walls  above  the  benches,  and  protection  from  burns  is 
given  by  wooden  gratings.  The  floor  of  the  building  is  clear  for  washing 
with  a  hose;  nothing  but  the  iron  supports  of  the  benches  interfere. 

In  Arizona,  during  a  large  part  of  the  year,  the  air  is  so  dry  that  clothes 
may  be  dried  without  heat  if  there  is  a  free  circulation  of  air.  To  furnish 
this,  ventilators  are  spaced  at  10-ft.  intervals  in  a  row  down  the  center  of 
the  building.  The  room  is  exceedingly  wide,  and  it  may  be  desirable  to 


SAFETY  AND  SANITATION  485 

provide  additional  ventilators.  It  would  be  even  better  to  leave  out  the 
flat  ceiling,  which  would  allow  the  air  to  pass  still  more  freely  through  the 
clothes.  Thin  sheets  of  galvanized  iron  separate  the  surface  and  mining 
clothes,  but  they  appear  to  be  unnecessary.  Miners  work  eight  hours  in 
the  Warren  district,  and  clothes  have  at  least  14  hr.  in  which  to  dry.  As 
soon  as  the  morning  shift  has  changed,  the  fire  is  banked  and  all  windows 
opened.  Little  fire  is  necessary  until  an  hour  or  an  hour  and  a  half  before 
the  shift  comes  up,  when  the  windows  are  closed  and  the  fire  freshened  to 
warm  the  room  arid  heat  water  for  bathing.  The  men  on  the  night  shift 
go  down  an  hour  and  a  half  after  the  day  shift  comes  up,  and  the  building 
is  still  warm  for  them  while  they  change  their  clothes.  The  fire  is  again 
allowed  to  die  down  and  is  started  up  to  warm  the  room  for  men  coming  off 
shift  at  1 : 30  a.m.  and  for  the  morning  shift  which  goes  on  at  7 : 30. 

The  cost  of  the  building  was  as  follows:  Excavation,  $303;  concrete 
foundation  walls,  and  floor,  $1589;  building,  $10,490;  heating  plant,  etc., 
$3056;  total,  $15,438.  The  building  is  large  enough  for  500  men,  but 
only  383  lockers  are  provided.  The  cost  of  extra  lockers  would  be  about 
$250  more,  making  the  cost  per  man  $31.37. 

The  buildings  have  not  been  constructed  long  enough  to  give  a  fair 
average  for  cost  of  maintenance.  The  expense  for  fuel  is  more  uniform, 
and  a  shorter  time  is  sufficient  to  give  dependable  costs.  It  was  found 
that  in  the  new  change  rooms  the  cost  of  fuel  per  man  for  a  period  of 
nine  months  ended  not  long  ago  was  only  72  per  cent,  of  that  of  the  older 
type.  None  of  the  new  change  rooms  is  used  to  its  full  capacity,  while  the 
older  buildings  are  crowded.  The  saving  in  fuel  per  man  would  be  even 
greater  if  they  also  were  filled.  It  may  be  safely  assumed  that  these 
buildings  will  cost  less  for  .repairs  than  the  earlier  type,  and  there  will 
be  an  important  saving  in  fuel.  There  is  also  a  great  improvement  in 
sanitation.  The  usual  rather  unpleasant  smell  of  drying  clothes  is 
not  present. 

Change  House  with  Swimming  Pools  (By  A.  H.  Sawyer). — A  new 
change  house  has  recently  been  completed  at  the  Raimund  mines  of  the 
Republic  Iron  &  Steel  Co.,  near  Bessemer,  Ala.  It  has  some  novel 
features  which  should  make  its  description  interesting.  The  building, 
illustrated  in  Fig.  407,  is  constructed  of  concrete  and  brick,  121  ft.  9 
in.  long  by  37  ft.  3  in.  wide  and  contains  365  lockers,  280  of  which  are 
for  colored  employees  and  85  for  white  employees,  including  5  in  the 
foremen's  office.  The  dimensions  of  the  building  give  11.5  sq.  ft.  per 
man.  If  the  portion  occupied  by  the  offices  and  swimming  pools  be 
excepted,  the  space  per  man  is  7.3  sq.  ft.,  which  is  less  than  in  most 
change  houses. 

The  swimming  pools,  one  for  white  and  one  for  colored  employees,  are 
27  ft.  long  and  17  ft.  wide  with  a  maximum  depth  of  8  ft.,  and  hold  21,292 


486 


DETAILS  OF  PRACTICAL  MINING 


gal.  up  to  the  overflow.  The  water  is  heated  by  live  steam  admitted 
through  pipes  into  the  bottoms  of  the  pools.  At  one  end  of  the  pool 
and  at  the  water  line  there  is  imbedded  in  the  concrete  a  3-in.  pipe  with  a 
slot  running  its  entire  length.  This  serves  as  an  overflow  pipe  and  also 
as  a  means  to  cleanse  the  surface  of  the  water.  No  one  will  be  allowed  to 
use  the  swimming  pools  unless  he  has  the  permission  of  the  mine  physician 
and  has  previously  taken  a  shower  bath. 

The  lockers  are  15  X  15  X  60  in.,  with  perforated  bottoms,  arranged 
in  rows  of  20  each;  they  rest  on  wrought-iron  supports  which  also  carry 
seats  12  in.  wide.  Under  each  double  row  of  lockers,  extending  its  full 


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FIG.    407.  -  SOUTHERN   CHANGE    HOUSE   WITH   SEPARATE    ACCOMMODATIONS   FOR  WHITES 

AND  NEGROES. 


length,  is  a  radiator  made  of  eight  l}^-m.  pipes,  giving  a  total  of  1300 
sq.  ft.  of  radiating  surface  for  heating  the  building.  Live  steam  under 
3-lb.  pressure  is  used.  Each  pair  of  rows  of  lockers  has  wash  basins, 
closet  and  urinal  at  the  rear,  separated  from  the  shower-bath  compart- 
ment by  galvanized-iron  partitions.  Two  sanitary  drinking  fountains  are 
provided,  one  in  the  white  and  one  in  the  colored  section. 

There  are  19  showers;  the  water  enters  a  mixing  chamber  through  hot- 
and  cold-water  pipes,  fitted  with  lock  valves,  below  which  are  stop  and 
waste  cocks,  so  that  the  quantity  of  water  for  each  shower  can  be  regu- 
lated by  the  attendant,  preventing  the  use  of  an  excessive  quantity  of 
water.  Above  the  mixing  chamber  is  a  valve  for  turning  the  water  on  and 


SAFETY  AND  SANITATION 


487 


off.  In  the  main  part  of  the  change  house,  there  is  one  shower  for  every 
20  men.  It  is  estimated  that  8  gal.  of  hot  water  will  be  sufficient  for  each 
bath.  This  water  is  heated  by  live  steam,  in  a  closed  heater  situated 
in  the  basement  of  the  building.  Room  has  been  allowed  here  for  the 
installation  of  an  independent  boiler  if  it  should  at  any  time  seem  desirable. 
The  building  is  lighted  by  incandescent  lamps,  12  in  the  large  room  and 
a  drop  light  in  each  of  the  small  rooms.  An  emergency  hospital  14  ft. 
3  in.  by  8  ft.  is  situated  just  off  the  foremen's  office  and  is  fitted  with  a 
wash  basin,  a  first-aid  outfit  and  an  ambulance  which  can  be  handled 
easily  by  one  man. 

United  Verde's  New  Change  House. — The  old  change  house  at  the 
United  Verde  mine  at  Jerome,  Ariz.,  was  replaced  by  a  modern  steel 


:-   160       


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PIG.    408. CHANGE    HOUSE    OP    THE    UNITED    VERDE,    JEROME,    ARIZONA.  - 

change  house  embodying  the  latest  ideas  in  sanitation  and  privacy, 
such  as  chain  " lockers"  of  the  Continental  type  and  individual  shower 
baths.  This  type  of  locker  was  adopted  in  the  new  change  houses  built 
by  the  Copper  Queen  at  Bisbee  and  by  the  Butte  &  Superior  at  Butte; 
the  new  United  Verde  change  house  is  based  on  the  experience  of  the  above 
two  companies,  but  certain  changes  were  made  to  suit  the  local  conditions 
and  to  increase  individual  privacy. 

The  building  is  50  X  160  ft.  with  accommodations  for  800  miners  and 
25  foremen  and  shift  bosses.  It  has  a  steel  frame  with  corrugated-iron 
sides  and  roof;  the  reinforced-concrete  floor  is  slightly  elevated  and  sup- 
ported on  the  steel  frame  so  that  the  building  may  be  leveled  in  case  of 
subsidence  of  the  ground.  The  site  is  at  the  mouth  of  the  50-ft.  adit, 


488  DETAILS  OF  PRACTICAL  MINING 

which  on  completion  of  the  change  house  became  the  main  entrance  to  the 
mine  for  the  miners.  The  mine  time  office  is  situated  just  inside  the 
entrance  to  the  change  house,  and  adjoining  is  an  emergency  hospital 
equipped  with  stretchers  and  other  supplies  for  first-aid  work.  The  fore- 
men's office  and  change  room  are  opposite  and  the  remainder  of  the  build- 
ing is  devoted  to  accommodations  for  the  miners. 

The  main  room  has  a  row  of  15  double  benches  and  two  single  benches 
at  each  end.  The  locker  system  consists  of  the  chain  lockers  already 
mentioned,  supplemented  by  small  metal  lockers,  15  X  14%  X  12  in., 
for  shoes,  soap,  etc.  These  small  metal  lockers  are  fastened  to  the  back 
of  the  benches  within  easy  reach,  and  the  chain  suspending  the  clothes 
is  locked  behind  the  hasp  of  the  metal  locker  by  a  single  padlock.  The 
miner's  clothes  are  suspended  from  a  cast-iron  frame  having  six  hooks. 
Between  each  of  the  double  benches  there  is  space  for  50  men. 

At  the  ends  of  the  benches  there  are  shower  baths  with  galvanized- 
iron  sides  and  a  canvas  front  curtain.  Along  the  sides  of  the  building 
there  are  144  enameled-iron  basins  equipped  with  the  usual  rubber  stop- 
pers, and  spring  faucets  to  prevent  waste  of  water,  which  is  important 
here.  The  basins  are  arranged  in  batteries  of  nine  and  empty  into  a 
trough  that  serves  an  entire  battery  and  discharges  into  a  trapped  drain 
pipe.  The  basins  are  hinged  and  may  be  swung  back  to  permit  the  clean- 
ing of  the  trough  by  an  attendant  after  the  miners  have  left.  The  con- 
crete floor  of  this  room  is  1J^  in.  higher  at  the  center  and  has  gutters 
along  each  side,  so  that  the  floor  may  be  flushed  and  readily  cleaned. 
The  building  is  provided  with  steam  heat,  and  is  well  .ventilated  through 
the  monitor  at  the  top  of  the  building.  There  is  an  attendant  on  each 
shift;  these  attendants  are  trained  in  first-aid  work  and  also  look  after  the 
emergency  hospital. 

Homestake  Two-story  Change  House  (By  B.  C.  Yates).— The  Home- 
stake  Mining  Co.,  of  Lead,  S.  D.,  recently  completed  and  put  into  service 
a  change  house  for  underground  men,  which  presents  some  new  features 
in  construction  and  equipment  that  may  be  of  interest.  The  building 
is  situated  near  the  Ellison  hoist,  and  was  designed  to  accommodate 
about  600  men.  The  walls  are  of  hollow  concrete  blocks  in  two  courses, 
giving  a  total  thickness  of  16J^  in.  The  ground  floor  is  of  plain  concrete 
laid  on  a  broken-stone  base,  and  the  second  floor  is  of  reinforced  concrete, 
supported  on  I-beams,  the  beams  covered  on  the  under  side  to  protect 
them  from  rust,  as  well  as  from  any  fire  that  might  occur  in  the  clothing. 
The  roof  is  of  steel  covered  with  Carey's  patented  cement  roofing,  laid 
on  1^-in.  sheathing.  There  is  no  ceiling  under  the  roof  trusses.  Three 
30-in.  Globe  ventilators  along  the  ridge  of  the  roof  assist  in  carrying  off 
foul  air  and  lessen  the  smell  which  is  always  present  where  rriany  damp 
working  clothes  are  kept.  The  window-glass  area  is  about  17  per  cent. 


AND  SANITATION 


489 


490 


DETAILS  OF  PRACTICAL  MINING 


of  the  entire  wall  area  and  is  distributed  in  such  a  way  as  to  give  efficient 
lighting  except  in  the  end  in  which  the  showers  are  located.  Here  the 
building  wall  forms  part  of  a  retaining  wall,  built  against  the  natural 
rock  bank  at  the  end  of  the  excavation. 

The  arrangement  of  the  building  is  shown  in  Figs.  409  and  410.  It 
is  heated  by  exhaust  steam  from  the  hoisting  engine,  the  steam  being 
carried  to  the  rear  end  of  the  building  in  two  12-in.  pipes  laid  under  the 
ground  floor  in  conduits  covered  with  steel  plates.  Here  the  pipes  are 
turned  and  carried  up  to  the  under  side  of  the  second-floor  beams,  re- 
turned to  the  front  end  of  the  building,  passed  up  through  the  second 
floor  to  the  bottom  chord  of  the  roof  trusses  and  finally  returned  to  the 
rear  end  and  passed  out  through  the  wall.  Water  for  wash  basins  and 


Sanitary  Fount 


4'Cold  from  Mam70  5e^er     Wash  Trough"' 
Corrugcrf-ed  5+eeJ  Cover      Benches      Lockers 


FlG. 


Telephone 

FIRST    FLOOR    PLAN 
410.  -  FIRST-FLOOR   PLAN   OF  THE   HOMESTAKE   CHANGE   HOUSE. 


showers  is  heated  by  steam  in  a  large  tank  heater  in  the  hoist  building 
nearby.  There  are  16  shower  stalls  with  partitions  made  of  galvanized 
iron  supported  on  a  framework  of  angle  iron.  A  patented  mixing  valve 
called  the  Niedecken  Mixer,  made  by  the  Hoffman  &  Billings  Mfg.  Co., 
Milwaukee,  Wis.,  is  used  to  control  the  supply  of  hot  and  cold  water  to 
the  showers. 

The  lockers  are  all  steel,  15  X  15  X-72  in.,  with  perforated  doors,  a 
top  shelf  for  hats  and  small  articles,  and  hooks  under  this  shelf  for  clothes, 
the  bottom  serving  as  a  shelf  for  boots.  Each  man  is  allotted  one  locker 
and  furnishes  his  own  lock  and  key.  The  galvanized-iron  wash-troughs 
are  set  along  the  walls  under  the  windows  and  hot-  and  cold-water  faucets 
are  spaced  about  24  in.  along  the  trough.  Each  man  is  supplied  with  a 
wash  basin,  which  he  keeps  in  his  own  locker.  A  room  in  one  corner  of 
the  first  floor  is  used  by  the  shift  bosses.  In  this  room  are  lockers,  a 
bath-tub  and  shower,  a  wash  trough,  a  desk  and  a  telephone.  This 
room  offers  opportunity  for  the  bosses  to  talk  over  their  work  privately 


SAFETY  AND  SANITATION  491 

and  permits  their  being  reached  by  telephone  before  going  down  into  the 
mine. 

LATRINES,  ETC. 

Sanitary  Underground  Latrine  (By  W.  B.  Hambly  and  A.  E.  Hall).— 
At  most  mines  the  problem  of  the  underground  privy  is  serious.  If  the 
men  are  allowed  to  go  to  the  surface  excessive  time  is  lost;  the  portable 
privies  frequently  used  are  generally  unsatisfactory,  if  the  waste  from 
the  privies  is  allowed  to  run  into  the  sump,  unless  pumping  is  frequent, 
there  is  danger  of  having  the  material  collecting  on  the  sump  bottom. 
Fig.  411  shows  the  design  of  a  privy  which  keeps  the  waste  materials 
entirely  separate  from  the  sump  and  is  a  unit  in  itself. 

The  device  is  simple.  It  consists  of  a  piece  of  12-in.  cast-iron  pipe 
or  any  sort  of  pipe  with  a  cap  on  each  end,  the  caps  bored  and  threaded 
for  a  4-in.  pipe.  The  intake  is  at  the  bottom  of  one  end  and  the  discharge 
at  the  top  of  the  other.  A  small  auxiliary  pipe,  inserted  at  one  end,  to  be 
used  as  a  run-off  after  flushing,  leads  to  the  sump.  Two  saddle  flanges 
are  placed  as  shown,  the  12-in.  pipe  being  cut  to  match.  The  saddle 
flanges  should  be  10-in.  A  10-in.  nipple  about  4  in.  long  is  placed  in  the 
saddle  and  on  the  nipple  is  screwed  half  of  a  flange  union.  A  wooden  seat 
is  attached  to  the  top  by  the  bolt  holes  in  the  union.  Flap  valves  must 
be  placed  inside  the  main  pipe  at  the  saddle  flanges  to  prevent  overflowing 
during  the  process  of  flushing.  A  valve  is  placed  in  the  water  column 
leading  from  the  pump  and  connections  are  made  on  either  side  of  this 
valve;  these  connections  are  also  provided  with  valves  as  shown.  The 
valves  are  all  placed  so  that  they  come  inside  the  pump  house;  only  the 
pump  man  has  access  to  them  and  he  is  responsible  for  the  flushing. 
When  the  privy  does  not  need  flushing,  valve  No.  1  is  open  and  No.  2 
and  No.  3  are  closed.  The  discharge  from  the  pump  is  then  up  the  shaft 
direct.  Valve  No.  3  is  a  gate  valve,  but  the  other  two  can  be  globe  valves. 
When  it  is  desired  to  flush  the  closet,  valve  No.  1  is  closed  and  No.  2  and 
No.  3  are  opened.  The  water  then  takes  the  indirect  course  through  the 
closet,  carrying  the  waste  to  the  surface.  When  it  has  been  flushed, 
valves  No.  2  and  No.  3  are  closed  and  valves  No.  1  and  No.  4  are  opened. 
As  shown,  there  are  only  two  seats,  but  any  convenient  number  can  be 
put  on. 

Septic  Tank  for  Underground  Latrine  (By  H.  G.  Pickard). — The  sep- 
tic tank  shown  in  the  accompanying  sketch  was  designed  for  the  Mond 
Nickel  Co.'s  Frood  Extension  mine  at  Sudbury.  The  Ontario  mining 
law  requires  the  provision  of  underground  closets,  and  the  Provincial 
health  laws  forbid  the  discharging  of  untreated  sewage  into  running 
streams.  At  the  best  the  ordinary  box  closet  is  a  nuisance,  and  there  are 
many  objections  to  running  untreated  sewage  through  the  pumps  to  the 


492 


DETAILS  OF  PRACTICAL  MINING 


f  if 


SAFETY  AND  SANITATION 


493 


surface.  To  overcome  the  objections  to  these  types  of  closets,  it  was 
decided  to  introduce  a  septic  tank.  The  stools  flush  automatically,  and 
discharge  through  a  pipe  into  the  tank,  which  may  be  located  at  any  point 
provided  there  is  sufficient  fall  from  the  tank  to  the  pump  sump.  Fig. 
412  shows  the  ideal  location,  since  the  excavations  for  sump  and  tank  may 
be  taken  out  at  one  operation. 

With  septic  tanks,  as  ordinarily  constructed,  it  is  found  necessary  to 
clean  out  from  once  or  twice  a  year  the  sediment  that  is  deposited.  To 
obviate  the  necessity  of  doing  this  cleaning  by  hand,  iron  pipes  having 
their  ends  drawn  to  flat  nozzles  are  inserted  in  the  concrete  lining  of  the 
tank.  The  pipes  are  bent  so  as  to  deflect  a  stream  of  water  toward  the 
centers  of  the  chambers.  A  bypass  from  the  pump  connects  with  the 


FIG.    412. ARRANGEMENT  OP  UNDERGROUND  SEPTIC  TANK. 

wash  pipes,  and  sediment  may  be  washed  into  the  sump,  where  it  will 
remain  long  enough  in  suspension  to  be  discharged  by  the  pump  before 
settling.  The  tank  shown  was  designed  to  accommodate  a  force  of  150 
men  per  day. 

Concrete  Latrine  at  the  New  United  Verde  Smelting  Plant. — At 
Clarkdale,  Ariz.,  a  special  effort  was  made  to  maintain  sanitary  condi- 
tions both  during  the  period  of  construction  and  later.  At  the  new 
smelting  plant  of  the  United  Verde  Copper  Co.  a  concrete  latrine  was 
provided,  connecting  with  the  general  sewerage  system  which  discharges 
into  a  septic  tank.  The  building  is  approximately  8  X  20  ft.,  sheathed 
with  No.  22  corrugated  iron.  The  general  arrangement  is  shown  in 
the  accompanying  drawings  by  Repath  &  McGregor,  Fig.  413,  who  de- 
signed the  new  works.  The  bottom  of  the  concrete  trough  has  a  slope 
Y±  in.  to  the  foot  and  the  flow  of  water  is  regulated  by  the  valve  at  the 
head  end,  while  at  the  outlet  there  is  a  double  trap  consisting  of  a  4-in. 


494 


DETAILS  OF  PRACTICAL  MINING 


lead  pipe  and  an  8-in.  tile  trap.  At  the  top  of  the  trough  on  each  side  is 
a  1-in.  perforated  pipe  that  constantly  sprays  the  sides.  The  rail  is  a 
polished  and  rounded  2  X  6-in.  plank  fastened  to  the  concrete  by  J^-in. 
hook  bolts.  To  insure  cleanliness  there  is  a  back  rail  placed  1  ft.  8  in. 
above  the  seat. 

Septic  Tanks  at  Clarkdale,  Arizona. — To  avoid  pollution  of  the  Verde 
River,  the  United  Verde  Copper  Co.  constructed  a  septic  tank  to  take 
the  sewage  from  the  new  smelting  plant  and  from  the  "  construction 
town"  at  Clarkdale.  Another  septic  tank  of  similar  size  was  constructed 
for  the  main  residence  portion  of  Clarkdale,  the  present  construction 
camp  becoming  the  "Mexican  town." 

The  septic  tanks  are  53  ft.  long  by  26  ft.  6  in.  wide,  constructed  of 
reinforced  concrete.  Each  tank  required  450  cu.  yd.  of  excavation  and 
115  cu.  yd.  of  concrete,  the  mixture  for  the  latter  being  1  :2^  :5.  The 


FIG.    413. CONCRETE     LATRINE,     UNITED    VERDE     WORKS,     CLARKDALE,    ARIZONA. 

approximate  cost  of  such  a  tank  is  from  $1500  to  $2000,  depending  upon 
the  locality  in  which  it  is  constructed.  The  tank,  designed  by  Repath 
&  McGregor  for  the  Clarkdale  works  and  construction  town,  is  shown  in 
Fig.  414.  The  tank  is  7  ft.  deep  and  is  designed  in  two  units  so  as  to 
permit  occasional  inspection  or  cleaning.  Following  the  receiving  com- 
partments, there  are  two  series  of  four  working  compartments  each. 
The  first  compartment  is  16  ft.  long,  the  second  12  ft.,  the  third  10  ft., 
and  the  fourth  8  ft.  The  connection  between  the  various  working  com- 
partments is  through  twelve  3-in.  pipes  in  the  partition  walls  about 
3  ft.  from  the  bottom  of  the  tank  and  at  an  angle  of  45°  for  the  purpose 
of  directing  the  flow  to  the  top  of  the  next  compartment.  The  tank  walls 
and  partitions  are  10  in.  and  the  bottom  6  in.  thick;  the  tank  is  covered 
with  reinforced-concrete  slabs,  6  ft.  4  in.  long,  15%  in.  wide,  and  3  in. 
thick.  When  for  any  purpose  entrance  to  the  tank  is  desired  these  con- 


SAFETY  AND  SANITATION 


495 


crete  slabs  may  be  removed,  but  during  the  normal  operation  the  slabs 
are  sealed  by  a  covering  of  earth  12  in.  thick  at  the  center  line  of  the  tank 
and  sloping  to  8  in.  at  the  sides.  No  air  is  permitted  to  enter  the  septic 
tank,  but  it  is  necessary  to  provide  for  the  removal  of  gases  formed  within 
the  tank,  and  this  is  accomplished  by  a  2-in.  ventilating  pipe  in  the  parti- 
tion walls  of  each  compartment,  the  gases  being  removed  through  a  3-in. 
ventilator  near  the  top  of  the  last  compartment. 


12-Sari, %"D,am  to'&ng 
^  16-Bar^'Diam.  18'Long 


V  A7rs&  "0iarrr.~2C 


/"*"*!"" 


X-SarT,J<"oinm.l4io, 

«  r 


i  I 


5.        i 


SB  in 

__i 


* 


SECTION  A-A. 


-,*- 


»ECTIOH  C-C 

'^^'m^/^a-rnfsh.^h^rscf.ff. 


COVER    PLAN 


m&&^'  "•^.s'.          i:.;,- 

»•  ,,^:^..,^ 


DETAIL  OFCONCRCTC^LAD 


Ts 
hkf 


1 

l^^g 

i    ! 

Coupling 

__:? 

*^l5!^"::::h^'~::^zi^*:~/?^:::::.^ 

A  DETAIL  Of 

FIG.    414. SEPTIC     TANKS     FOR    SEWAGE     DISPOSAL,     CLARKDALE,     ARIZ. 

The  sewage  enters  the  septic  tank  about  6  in.  below  the  top  through 
an  8-in.  trapped  iron  pipe  that  delivers  the  material  to  a  receiving  box, 
a  trough  on  each  side  connecting  with  receiving  compartments,  2  ft.  by 
11  ft.  4  in.  by  7  ft.,  from  which  the  sewage  passes  through  12-in.  slots 
about  2  ft.  above  the  bottom  to  the  two  series  of  working  compartments. 
The  disintegration  of  the  organic  material  in  the  septic  tank  is  brought 
about  by  the  anaerobic  bacteria,  i.e.,  those  which  live  and  act  only  in 
the  absence  of  air.  The  material  entering  the  tank  separates' into  three 


496  DETAILS  OF  PRACTICAL  MINING 

portions :  A  solid  portion  which  sinks  to  the  bottom,  a  liquid  layer  in  the 
center,  and  a  portion  which  floats  at  the  top  of  the  liquid.  By  the  action 
of  the  anaerobic  bacteria  the  solid  floating  and  settled  portions  are  gradu- 
ally converted  into  liquid  and  pass  through  the  pipe  connections  in  the 
partition  walls  to  the  succeeding  compartments  and  out  through  a  4-in. 
pipe  about  2J^  ft.  above  the  bottom  of  the  last  compartment.  Most  of 
the  work  is  accomplished  in  the  first  compartment  and  the  succeeding 
compartments  are  gradually  reduced  in  length.  The  outlet  pipe  from 
each  series  of  compartments  leads  to  a  spreading  weir,  40  ft.  long  by 
about  2  ft.  wide,  over  which  the  effluent  passes  in  a  thin  layer  to  a  gravel 
bed  about  40  ft.  square  where  purification  is  finally  accomplished  by 
aerobic  bacteria  and  sunlight.  While  the  organic  material  in  the  sewage 
is  rendered  innocuous  by  this  treatment,  no  attempt  is  made  to  deodorize 
the  released  gases.  The  septic  tank  should  consequently  be  built  at 
some  distance  from  any  residences  or  other  inhabited  buildings.  There 
are  many  mining  communities  where  sanitary  conditions  could  be  vastly 
improved  at  comparatively  small  expense  by  the  installation  of  a  system 
of  this  sort. 

FIRST  AID 

First-aid  Bandage  Roller  (By  E.  W.  R.  Butcher). — Fig.  415  shows  a 
bandage  roller  used  by  the  Republic  Iron  &  Steel  Co.,  on  the  Mesabi 
range,  in  its  first-aid  work.  The  different  classes  are  required  to  do  prac- 


PIG.  415. DEVICE  FOR  ROLLING  BANDAGES. 

tice  work  in  their  course  of  training  and  the  ordinary  method  of  rolling 
bandages  by  hand  was  found  too  tedious  for  the  large  number  which  had 
to  be  rolled.  This  device  was  designed  from  a  wooden  one  somewhat 
similar  to  it  which  was  being  used  by  one  of  the  range  hospitals.  The 
bandage  to  be  rolled  is  brought  under  the  rod  A,  over  the  rod  B,  under  the 
rod  C,  and  given  about  three  turns  around  the  rod  D.  The  left  hand  is 
then  placed  on  the  bandage,  pressing  it  against  the  table  to  which  the 
roller  is  attached,  and  it  is  rolled  to  any  degree  of  tightness  by  regulating 
the  pressure  of  the  hand  on  the  bandage.  One  edge  is  kept  close  to  the  far 
side  of  the  frame.  The  bandage  can  be  removed  by  taking  out  the  pin  E, 


SAFETY  AND  SANITATION 


497 


which  allows  the  crank  and  rod  to  come  out,  so  that  the  bandage  can  slide 
off  the  rod. 

Resuscitation. — The  U.  S.  Bureau  of  Mines  in  Technical  Paper  77, 
gives  the  report  of  the  committee  on  resuscitation  from  mine  gases.  The 
committee  was  composed  of  doctors.  After  reviewing  the  committee 
report,  the  Bureau  engineers  made  the  following  recommendations  in  cases 
of  gassing  or  shock: 

In  case  of  gassing,  remove  victim  at  once  from  gaseous  atmosphere. 
Carry  him  quickly  to  fresh  air  and  immediately  give  manual  artificial 
respiration.  Do  not  stop  to  loosen  clothing.  Every  moment  of  delay 


Top  Plan 


\\— 


Reinforcement ' 
sfra/x  sewed to 
canvas 


Reinforcement- 
Strap 


Side  Elevation 


Bottom  Plan 


PIG.    416. THREE  VIEWS  OF  NEW  JERSEY  ZINC  CO.   STRETCHER. 

is  serious.  In  case  of  electric  shock,  break  electric  current  instantly. 
Free  the  patient  from  the  current  with  a  single  quick  motion,  using  any 
dry  nonconductor,  such  as  clothing,  rope,  or  board,  to  move  patient  or 
wire.  Beware  of  using  any  metal  or  moist  material.  Meantime  have 
every  effort  made  to  shut  off  current.  Attend  instantly  to  the  victim's 
breathing.  If  the  victim  is  not  breathing,  he  should  be  given  manual 
artificial  respiration  at  once.  If  the  patient  is  breathing  slowly  and 
regularly,  do  not  give  artificial  respiration  but  let  nature  restore  breathing 
unaided. 

In  gas  cases,  give  oxygen.  If  the  patient  has  been  gassed,  give  him 
pure  oxygen,  with  manual  artificial  respiration.  The  oxygen  may  be 
given  through  a  breathing  bag  from  a  cylinder  having  a  reducing  valve, 

32 


498  DETAILS  OF  PRACTICAL  MINING 

with  connecting  tubes  and  face  mask,  and  with  an  inspiratory  and  expira- 
tory valve,  of  which  the  latter  communicates  directly  with  the  atmos- 
phere. No  mechanical  artificial  resuscitating  device  should  be  used 
except  possibly  one  operated  by  hand  that  has  no  suction  effect  on  the 
lungs.  Use  the  Schaefer  or  prone  pressure  method  of  artificial  respira- 
tion. Begin  at  once.  A  moment's  delay  is  serious.  Continue  the 
artificial  respiration.  If  necessary,  continue  two  hours  or  longer  without 
interruption  until  natural  breathing  is  restored.  If  natural  breathing 
stops  after  being  restored,  use  artificial  respiration  again. 

Do  not  give  the  patient  any  liquid  by  mouth  until  he  is  fully  con- 
scious. Give  him  fresh  air,  but  keep  his  body  warm.  Send  for  the 
nearest  doctor  as  soon  as  the  accident  is  discovered. 

Underground  Stretcher  (Bull.,  Mining  &  Metallurgical  Society  of 
America). — Fig.  416  shows  a  stretcher  for  underground  use  employed  at 
the  Franklin  Furnace  mine  of  the  New  Jersey  Zinc  Co. 

MISCELLANEOUS 

Fire-fighting  Pipe  Lines  at  Mount  Morgan  (By  B.  Magnus). — To 
deal  successfully  with  a  fire  discovered  in  its  initial  stage,  it  is  essential 
that  a  supply  of  water  under  a  good  pressure  should  be  immediately 
available  at  the  scene  of  the  outbreak.  To  make  this  possible,  fire  hoses 
and  suitable  connections  to  the  network  of  pipe  lines  which  supplies 
water  for  use  with  the  rock  drills  have  been  provided  for  the  Mount 
Morgan  Mine  in  Queensland,  Australia,  at  convenient  points  on  the 
various  levels.  Every  working  face  has  water  pipe  laid  to  it,  which  by 
means  of  a  J^-in.  rubber  hose,  supplies  the  necessary  spray  for  boring  and 
allaying  the  dust,  consequently  this  pipe-line  system  is  always  full  of 
water.  The  pipes,  however,  are  only  l^  m-  m  diameter,  much  too  small 
to  supply  sufficient  water  if  a  fire  once  gained  a  firm  hold.  To  furnish 
immediately  abundant  water,  the  underground  air  mains  are  connected 
with  the  surface  reservoirs,  so  that  within  a  few  minutes  after  an  alarm  is 
given  the  8-in.  air  mains  can  be  conveying  water  to  the  place  of  the  fire. 
This  is  effected  by  shutting  off  the  air  and  opening  the  water-connection 
valves,  thus  giving  the  water  free  access  to  the  air  mains. 

The  accompanying  section,  Fig.  417,  will  assist  in  coming  to  an  under- 
standing of  the  system.  To  reduce  the  excessive  head  of  water  which 
would  result  if  no  break  were  made  in  the  circuit,  open  tanks  are  placed 
at  several  points,  underground  and  on  the  surface,  at  B,  D  and  E,  as 
indicated  on  the  section.  These  tanks  are  provided  with  ball  float  valves 
which  automatically  keep  them  full.  The  reservoir  marked  A,  situated 
on  the  original  hillside  at  the  south  end  of  the  opencut,  supplies  water  to 
the  tank  B.  For  fire-fighting  between  the  450-ft.  level  and  the  574-ft. 


SAFETY  AND  SANITATION 


499 


level,  the  pressure  is  obtained  from  B,  which  is  situated  87  ft.  above  the 
450-ft.  level;  on  the  574-ft.  level,  therefore,  the  head  is  211  ft.  A  second 
rese'rvoir  marked  C  stores  the  water  for  the  lower  levels.  It  supplies  a 
tank  marked  Z>,  provided  with  a  float  valve,  which,  in  its  turn,  supplies 
the  tank  E  on  the  650-ft.  level.  From  this  last,  the  water  is  drawn  for 
the  750-ft.,  the  850-ft.  and  the  950-ft.  levels. 

One  great  advantage  of  using  the  air  pipes  is,  that  a  supply  of  water  is 
assured  at  every  working  place.  In  the  event  of  fire,  the  rock-drill  hoses, 
which  are  1  in.  in  diameter,  can  be  used  as  water  hoses.  To  supplement 
these  hoses  there  are  on  the  main  levels,  connections  to  the  standpipes  for 
2-in.  canvas  hoses.  Printed  directions  regarding  the  opening  and  closing 
of  valves  are  posted  in  conspicuous  places,  so  that  the  uninitiated  may  be 
able  to  manipulate  them.  Once  the  water  is  turned  into  the  air  mains, 
the  valves  regulating  the  supply  of  air  in  its  ordinary  course  will  serve  to 
direct  the  water  to  wherever  it  is  needed. 


Tank  on  Southern  Edge 
of    Open  Cot 


Tank  at   Mouth  of 
Linda  Tunnel 
D 


FIG.    417. SECTION   SHOWING   PIPE   LINES   FOR   FTT>m    FIGHTING. 

While  such  an  arrangement  as  this  would  be  dangerous  if  there  were 
a  possibility  that  men  might  be  cut  off  by  a  fire  in  such  a  way  as  to  be  left 
dependent  on  the  Compressed  air  to  escape  suffocation,  the  layout  of  this 
particular  mine  renders  such  an  occurrence  exceedingly  unlikely.  The 
two  main  entrance  and  exit  shafts  are  at  the  extreme  southeast  end  ,of 
the  workings,  which  trend  in  general  northwest  and  southeast.  At  the 
far  northwest  end  of  the  workings,  a  ventilating  shaft  supplies  an  emer- 
gency exit.  It  is  considered  that  these  openings,  in  connection  with  the 
interlevel  winzes  and  ladderways,  reduce  to  a  minimum  the  possibility 
of  trapping  and  suffocation. 

Sanitary  Fountain  Made  from  Cask  (By  E.  C.  Carter). — Fig.  418 
shows  the  water  casks  used  in  the  mines  of  the  Gold  Hill  &  Iowa  Mines 
Co.,  at  Quartzburg,  Idaho.  Small  wine  casks  are  used  for  this  purpose, 
and  furnish  a  sanitary  and  inexpensive  method  of  supplying  water  to  the 


500 


DETAILS  OF  PRACTICAL  MINING 


different  parts  of  the  mine.  The  carmen  generally  send  these  kegs  to  the 
surface  with  the  first  car  out  on  each  shift,  thus  keeping  the  water  fresh 
and  cool.  By  giving  the  keg  a  slight  slant  toward  the  front  sufficient 
force  is  obtained  to  drive  the  water  from  the  J^-in.  pipe  until  the  keg  is 
practically  empty. 

[If  it  were  found  that  the  arrangement  as  presented  offered  a  tempta- 
tion to  suck  out  the  water  when  it  was  low,  a  head  could  be  obtained  at 
all  times  by  dropping  the  opening  below  the  bottom  of  the  barrel,  using 
three  ells  instead  of  one.  If  this  were  done,  merely  opening  the  stopcock 
would  always  insure  an  immediate  flow  of  water. — EDITOR.] 


AirVent/Jandte 
-Baft 


FIG.    418 SANITARY  UNDERGROUND   DRINKING   CASK 


Home-made  Shower  Bath  (By  E.  W.  R.  Butcher). — A  novel  shower 
bath  recently  constructed  by  the  volunteer  fire  department  of  the  Schley 
mine,  at  Gilbert,  Minn.,  contains  interesting  features  of  value  to  anyone 
desiring  .to  construct  a  shower  bath  at  small  cost.  The  hall  near  which 
the  men  carried  on  their  training  was  some  distance  from  the  mine,  and  it 
was  not  possible  to  use  mine  steam  for  heating  the  shower-bath  water; 
consequently  some  other  scheme  had  to  be  devised,  and  it  was  decided  to 
use  electric  current. 

A  small  building,  8  X  14  ft.,  situated  in  back  of  the  fire  hall,  had  been 
used  as  a  woodshed ;  it  was  cleaned  out  and  made  into  the  bathhouse.  A 
hot- water  tank  was  erected,  consisting  of  a  6-ft.  piece  of  old  15-in.  water- 
column  pipe.  This  pipe  was  closed  at  both  ends  with  a  %-in.  piece  of 


SAFETY  AND  SANITATION 


501 


plate,  the  upper  end  being  braced  with  two  2J^-in.  angle  irons.  The 
arrangement  of  the  piping  is  self-explanatory  in  Fig.  419.  An  electric 
heating  coil  surrounds  a  1-in.  pipe.  This  pipe  is  covered  with  a  single 
layer  of  uncut  mica,  on  which  is  wound  the  heating  element,  consisting  of 
25  ft.  of  No.  22  Calido  Element  wire.  The  vertical  pipe  is  attached  to  two 
horizontal  nipples  with  Navy  ground-joint-union  connections  to  provide 
easy  access  to  the  tank;  the  nipple  connects  to  the  hot-water  tank.  A 
mixing  chamber  for  hot  and  cold  water  is  provided,  consisting  of  a  piece  of 
5-in.  pipe,  the  ends  of  which  are  closed  by  two  plates  welded  on.  The 
sprinkler  of  the  shower  itself  was  made  from  a  K6~m-  copper  plate.  The 
upper  part  was  cupped  out  and  the  lower  part  punched  thoroughly  with 
small  holes. 


Room  Outline  '-. 


Light  in  Ceiling 


Hot  Water  Tank. 

15" Water  Column 

Pipe 


Mixing  /• 
Chamber 
5"Pipe 


I  Pipe  with  heating 
coil 


Drain  Valve  and  Tee 


Floor 


FIG.    419. LAYOUT   OF   HOMEMADE    SHOWER  BATH. 

Two  rubbing  appliances  were  made,  a  one-hand  and  a  two-hand.  The 
two-hand  was  made  from  J4~m-  flexible  shafting  and  the  one-hand  from 
34-in.  solid  shafting.  The  shafting  in  both  cases  was  strung  its  whole 
length  outside  the  handles  with  soft-rubber  washers  drilled  eccentric 
which  gave  an  excellent  kneading  effect.  Towels  were  made  from  cement 
sacks  which  were  ripped  and  washed  thoroughly.  The  men  stated  that 
they  were  just  as  good  as  bath  towels. 

Removable  Chute-spray. — A  recent  act  of  the  Nevada  legislature 
made  it  compulsory  to  put  sprinkling  devices  on  all  underground  ore 
chutes  where  dry  and  dusty  ore  is  handled.  In  Fig.  420  is  shown  a  con- 
venient form  of  spray  in  use  at  the  Mason  Valley  mine  for  laying  the 
dust  when  loading  cars.  All  stoping  is  done  by  the  shrinkage  method  and 


502 


DETAILS  OF  PRACTICAL  MINING 


as  large  boulders  are  unavoidably  covered  in  the  stopes,  frequent  blasting 
at  the  chute  mouths  is  necessary;  the  spray  was  designed  to  meet  this 
condition.  Water  is  piped  into  the  mine  through  a  1-in.  main,  and  a  1-in. 
pipe  is  brought  up  beside  each  chute  to  a  height  of  4  ft.  To  this  pipe,  by 
suitable  fittings,  as  shown,  is  connected  a  ^2-in.  globe  valve;  a  J^-in. 


Hook  -&  Round  Iron  fla 
at  end  to  fit  hanger 


FIG.    420. ARRANGEMENT    OP    SPRAY    AT   CHUTE    MOUTH. 


rubber  hose;  and  then  the  spray  proper.  The  spray  consists  of  a  2-ft. 
length  of  3^-in.  pipe,"  plugged  at  one  end  and  perforated  by  small  holes, 
placed  in  a  row  and  at  1-in.  spaces.  To  the  spray  pipe  is  bolted  the 
hanger.  This  is  a  piece  of  1  X  ;Nrm-  won,  bent  to  fit  the  hook.  The 
hook  is  made  of  a  short  length  of  a  %-in.  round  iron,  one  end  bent  at  right 


SAFETY  AND  SANITATION  503 

angles  and  flattened,  the  other  end  pointed  and  driven  into  a  wood  plug  in 
a  drill  hole  in  the  roof  of  the  drift.  The  flat  hook  and  the  fit  of  the  hanger 
prevent  the  spray  from  swinging,  so  that  the  water  is  always  thrown  in  the 
right  direction.  This  spraying  device  is  simply  and  cheaply  constructed; 
the  water  can  be  easily  regulated  by  the  carman  and  is  always  directed 
to  the  right  spot;  the  spray  can  be  swung  to  one  side  when  it  is  necessary 
to  blast  the  chute,  and  the  hook,  the  only  part  liable  to  injury  by  blasting, 
can  be  easily  replaced. 


XIII 


DRAINAGE  AND  VENTILATION 

Pumps  and  Parts — Air  Lifts — Sealing  off  Water — Ventilating  Devices 
PUMPS  AND  PARTS 

Unwatering  Shaft  with  Horizontal  Turbine  Pumps  (By  L.  C.  Moore). 
—The  Dexter  mine,  7  miles  west  of  Ishpeming,  Mich.,  was  shut  down  in 
1896  and  the  pumps  were  pulled.  In  the  spring  of  1914  the  Cleveland- 
Cliffs  company,  now  in  control,  decided  to  unwater  it  for  exploration 
purposes.  The  shaft  is  12  ft.  long  and  3J/£  ft.  in  minimum  width  and 
dips  at  an  angle  of  54°.  It  is  approximately  600  ft.  deep  on  the  incline 
and  has  eight  levels.  Most  of  the  water  enters  on  the  second  or  200-ft 


A.-./0'.K  10*  Runner 
B.../' 'Wire  Rope 
1-..3- Wire  Cable 

D. Telephone  Line 

t....6rP/pe 


• tf*  Valve 

6 2"  Bypass  Valve 

H~2S' of  4"  Discharge  Hose 
L-JeJephone 
K.-Porentia/  Starter 
L-50Hp.  L,600gal.200'Head 
M.-S1' Suction  Hose 
*\-..Guide  Shoe    ' 
Q..Ree  I  holding  650  of  cable 
f?...6"x  8'  'Runner 
Q.-d'x  10" Skid  Runner 

^.Ladder 
'',.      5—6"  Pipe 

•\..PIank  Slide 


X 


FIG.  421. LAYOUT  OP  PUMP  IN  SHAFT,  ARRANGED  FOR  LOWERING. 

level,  but  streams  were  encountered  also  on  the  third  and  seventh  levels. 
The  pumping  equipment  when  the  job  was  completed  consisted  of  one 
200-ft.  head,  600-gal.  per  minute  turbine  pump  and  two  400-ft.  head, 
300-gal.  turbine  pumps,  with  motors,  starting  boxes,  etc.,  complete. 
The  motors  were  50-hp.,  2200-volt,  60-cycle  machines,  interchangeable 
to  make  the  outfit  more  flexible.  The  shaft  pump  was  mounted  on  a 
skid,  as  shown  in  Fig.  421,  while  the  lead-covered  cable  reel  was  mounted 
on  a  lighter  skid  just  above  the  pump.  The  smaller  reel  shown  contains 
the  duplex  telephone  wire,  one  telephone  being  placed  on  the  skid  and  one 

504 


DRAINAGE  AND  VENTILATION  505 

in  the  engine  house.  All  communication  and  signaling  were  carried  on 
with  the  telephone. 

Pumping  operations  started  May  3  and  the  mine  was  completely  un- 
watered  on  July  17.  When  the  200-ft.  level  was  reached  the  600-gal. 
pump  was  set  off,  a  300-gal.  pump  installed  in  its  place  and  the  work  in 
the  shaft  completed  with  the  latter.  The  third  pump  was  installed  on  the 
third  level  to  take  care  of  the  shaft  water  when  the  shaft  pump  got  be- 
yond its  head  and  could  not  throw  to  the  surface.  The  incoming  water 
amounts  to  approximately  400  gal.  per  minute.  Storms  made  some 
trouble;  one  breakdown  of  the  transmission  line  caused  an  eight-hour  de- 
lay and  a  drowned  pump.  This  happened  on  a  Thursday,  but  by  the  next 
Monday  the  pump  was  recovered  and  the  motor  dried  out  and  back  in 
commission  again.  The  advantages  of  the  system  lay  in  the  ease  with 
which  the  pumps  handled  the  water  with  a  variation  in  head  from  50  ft. 
to  200  ft.;  the  low  head  room  required;  the  light  foundations  needed  for 
satisfactory  operation;  the  quick  changes  that  could  be  made  in  position; 
and  the  reliability  of  the  turbine  pumps  under  all  conditions. 

Economical  Pump  Arrangement  (By  Howard  S.  Lee). — At  the  Rain- 
bow mine  in  eastern  Oregon  it  became  necessary  to  provide  an  additional 
pump  to  take  care  of  extra  water  encountered  in  development  work  on 
the  lowest  level.  In  order  to  be  able  to  handle  surges  of  water  and  still 
not  incur  the  expense  of  a  pump  with  a  capacity  much  greater  than  the 
normal  flow,  an  installation,  as  shown  in  Fig.  422,  was  devised  by  E.  A. 
Hamilton,  master  mechanic.  While  the  arrangement  is  not  entirely 
original,  it  may  be  of  interest  to  those  having  similar  problems  on  account 
of  its  low  initial  cost  and  its  operating  economy  as  regards  both  labor  and 
power. 

The  pump  already  in  use  was  an  Alberger,  four-stage  centrifugal,  with 
a  capacity  of  100  gal.  per  minute,  direct  connected  to  a  motor  with  a  speed 
of  3600  r.p.m.  This  pump  was  connected  to  storage  tanks  on  the  hillside 
about  80  ft.  vertically  above  the  collar  of  the  shaft,  and  the  water  thus 
pumped  was  used  in  the  mill  or  allowed  to  overflow  to  waste.  The  new 
pump  is  a  Goulds  triplex  with  a  capacity  of  175  gal.  per  minute.  It  is 
connected  by  an  endless  balata  belt  to  a  25-hp.  motor.  In  order  to  place 
the  belt  and  motor  back  against  the  wall  and  out  of  the  way,  the  crank- 
shaft and  countershaft  were  turned  end  for  end.  An  idler  was  applied 
to  the  top  or  slack  side  of  the  belt  to  give  greater  pulley  contact  and 
eliminate  vibration  due  to  belt  whip.  Both  the  pump  and  motor  were 
placed  on  wooden  foundations  to  save  the  cost  of  concrete.  The  sills 
were  well  braced  and  securely  bolted  and  there  is  no  appreciable  vibra- 
tion. The  motor  foundation  was  built  21  in.  higher  than  the  pump  foun- 
dation, which  will  permit  2J^  ft.  of  water  on  the  floor  of  the  station  before 
the  motor  is  submerged.  The  pump  was  set  above  the  sump  to  eliminate 


506 


DETAILS  OF  PRACTICAL  MINING 


unnecessary  bends  in  the  suction  and  make  ifc  as  short  as  possible.  A  by- 
pass to  the  sump  and  a  check  valve  were  placed  in  the  discharge  column 
of  the  triplex  pump  and  the  flow  of  water  governed  by  an  angle  float- 
valve  in  the  bypass.  Between  the  two  sumps  there  is  a  ditch  2  ft.  deep 
and  the  float  works  within  this  range.  By  this  arrangement  the  centrifu- 
gal pump  can  never  be  without  water  and  only  the  excess  passes  through 
the  triplex  pump.  It  would  have  been  possible  to  connect  both  pumps 
to  the  same  water  column,  but  as  there  was  already  another  column  in 
the  shaft  which  discharged  into  an  old  adit  about  160  ft.  vertically  below 
the  storage  tanks,  this  was  used.  Now  only  such  water  as  is  needed  in  the 
mill  is  pumped  to  the  higher  level;  the  excess  is  discharged  at  the  lower 
level,  thereby  saving  power. 

To  regulate  further  the  flow  of  water,  a  bulkhead  was  placed  in  the 
main  crosscut  which  may  be  closed  when  the  power  is  off  or  when  it 
becomes  necessary  to  reduce  the  amount  of  water  entering  the  sump. 


FIG.  422. — LAYOUT  OP  PUMPS,  SUMPS,  DITCH  AND  CONTROL  VALVE. 

This  bulkhead  was  made  of  two  thicknesses  of  1-in.  lumber  and  provided 
with  a  felt  gasket  next  to  the  timber.  It  is  hinged  at  the  top  and  when 
closed  may  be  fastened  with  bolts  and  wing  nuts.  A  6-in.  pipe  and  valve 
were  provided  so  that  all  water  can  be  drained  before  the  bulkhead  is 
opened.  A  short  section  of  track  may  be  removed  when  the  bulkhead 
is  closed.  When  in  place  the  track  is  fastened  by  four  loose  pins.  By 
this  arrangement  the  flow  of  water  can  be  regulated  absolutely.  In 
case  of  power  interruption  it  is  not  necessary  to  use  the  auxiliary  steam 
pump  to  keep  the  electrical  pumps  from  being  flooded  and  the  expense  of 
fuel,  firemen  and  pumpmen  in  these  emergencies  is  eliminated.  In  addi- 
tion to  this  the  triplex  sump  acts  as  a  settling  sump  and  no  grit  can  enter 
the  centrifugal  pump.  With  the  float-valve  arrangement  the  water  is 
maintained  at  a  constant  level  and  no  pumpman  is  required. 

Homemade  Hand  Pump.— A  convenient  hand  pump  for  incidental 
work  around  a  mine  can  be  made  at  slight  expense.     Fig.  423  represents 


DRAINAGE  AND  VENTILATION  507 

such  a  pump,  using  a  2^-in.  pipe.  The  pump  in  its  simplest  form  will 
not  suck,  but  the  plunger  must  work  in  the  water.  By  the  attachment  of 
a  check  valve  at  the  bottom  of  the  pipe,  however,  a  suction  lift  could  be 
had.  For  its  construction,  three  %-in.  rods  are  welded  to  the  end  of  a 
}/2-in.  rod,  the  latter  of  the  same  length  as  the  pipe  through  which  the 
pumping  is  to  be  done.  The  three  rods  are  turned  or  swaged  to  %e  m- 
at  the  lower  ends  to  pass  through  the  plunger  and  are  threaded.  Trie 
plunger  pieces  are  held  against  the  %2-in.  collars  on  the  rods  by  nuts. 
The  plunger  consists  of  two  brass  disks  J£  in.  thick  with  a  piece  of  leather 
between.  The  lower  disk  fits  loose  in  the  pipe.  The  upper  disk  is 
slightly  smaller.  Thus  the  leather  will  have  a  slight  upward  turn  on  its 
edges  and  will  be  tight  in  the  pipe  when  the  plunger  rises  and  loose 
enough  when  it  descends,  to  permit  easy  working.  A  %-in.  hole  through 
the  plunger  is  covered  with  a  leather  flap  riveted  to  the  plunger  on  one  side 
and  weighted  down  with  a  brass  cap.  This  forms  the  working  valve. 

Leather 
brass  Disks /  Flap  Valve 

• 


L     ''Leaf her  Washer     ..„  J 

K-----  14 "  ""H 

FIG.    423. SIMPLE  HAND  PUMP  FOR  2^-IN.  PIPE. 

Hand -controlled  Compressed-air  Pumping  Barrel  (By  Arthur  0. 
Christensen). — The  homemade  arrangement  here  described  has  been 
found  useful  in  bailing  out  winzes  or  underhand  stopes  where  the  amount 
of  water  is  not  sufficient  to  pay  for  installing  a  pump,  while  the  lift  is  too 
high  to  bail  by  hand;  and  also  in  situations  where  a  pump  is  not  desirable 
because  of  blasting,  or  lack  of  room,  or  cost  of  moving  and  installing,  or 
because  none  is  to  be  had.  The  barrel,  rigged  as  illustrated  in  Fig. 
424,  can  readily  be  put  in  place  and  operated  with  the  same  air  and  even 
the  same  hose  as  is  used  to  run  the  drills.  Into  the  upper  side  of  the  bar- 
rel is  screwed  a  1-in.  nipple  which  has  a  1-in.  to  1  J^-in.  bushing  for  a  hose 
spud.  Into  the  bottom  is  screwed  a  2-in.  nipple.  A  few  weights,  such  as 
pieces  of  track  rails,  drill  steel  or  tripod  weights,  are  bound  to  the  bottom 
to  act  as  ballast  and  sink  the  barrel,  thereby  hastening  its  filling. 

In  operation,  the  air-discharge  cock  is  opened,  allowing  the  barrel  to 
fill  and  sink.  As  soon  as  air  ceases  to  issue  from  this  cock,  it  is  closed  and 
the  compressed  air  is  turned  on.  The  water  in  the  barrel  is  now  forced 
up  the  discharge  hose  until  air  begins  to  issue  with  the  water,  showing  the 
barrel  to  be  empty.  When  so  much  of  the  water  has  been  pumped  out 
that  the  barrel  no  longer  fills,  the  hose  is  unscrewed  from  the  top,  a  funnel 


508 


DETAILS  OF  PRACTICAL  MINING 


inserted  and  the  last  of  the  water  bailed  by  hand  into  the  barrel.  The  hose 
is  then  screwed  on  again  and  the  apparatus  operated  as  before.  The 
check  valve  between  the  barrel  and  the  discharge  is  not  necessary  unless 
there  is  a  possibility  of  the  discharge  line  siphoning  back  the  discharged 
water  while  the  barrel  is  filling  again.  This  operation  might  be  made 
automatic,  but  a  regular  trap  or  ordinary  pump  would  be  more  service- 
able in  such  a  case.  The  device,  lifting  water  30  ft.  with  an  air  pressure 
of  100  Ib.  per  square  inch,  and  an  average  difference  of  2  ft.  in  water 


Air  Discharge 


-Check  Valves 
FIG.    424. — VALVES    AND    CONNECTIONS    FOR    PUMPING    BARREL. 

levels  between  that  inside  and  that  outside  the  barrel,  should  handle  25 
to  30  gal.  per  minute.  With  a  2-in.  discharge  pipe  or  a  10-ft.  submer- 
gence, this  rate  would  be  nearly  doubled. 

Cast-steel  Pump  Valve. — A  valve  designed  and  patented  by  J.  P. 
Matthews,  of  the  Rogers-Brown  Ore  Co.,  is  illustrated  in  Fig.  425.  It 
was  found  in  the  operations  of  this  company  on  the  Cuyuna  range  that 
the  solid  rubber  valves  on  the  underground  pumps  were  expensive  in  the 
first  place  and  required  constant  changing.  The  new  valve  is  designed 


DRAINAGE  AND  VENTILATION 


509 


to  consist  principally  of  steel;  a  casting  is  made  as  light  as  possible  by 
being  built  in  skeleton  form  and  reinforced  with  ribs  and  two  circular 
grooves  are  left  to  receive  packing  rings  of  rubber  or  other  available 


WORKING    FACE  •'?**+**  i  I*  HALF    TOP    PLAN 

FIG.    425. CAST-STEEL  SKELETON  VALVE  TO  HOLD  RUBBER  PACKING. 

material.  The  packing  soon  wears  flush  with  the  steel  and  thereafter 
wear  on  the  whole  valve  is  much  slower.  The  arrangement  obviously 
saves  rubber  in  the  first  place  and  also  gives  the  valve  a  longer  life.  It  is 
stated  to  be  eminently  satisfactory  in  service.  The  valve  illustrated  is 


O  0VO  CD 
0  0-0- 

o  o  o 


FIG.    426. SUCTION  INLET  FOR   UNDERGROUND   PUMP. 

for  the  smaller  type  of  Prescott  pump  used  by  the  company;  for  the 
larger  pump,  however,  the  only  change  is  in  the  dimensions. 

Suction  for  Station  Pump  (By  H.  L.  Botsford). — Fig.  426  shows  a  suc- 
tion for  a  24-40-7   X   36-in.  pumping  engine.     The  area  of  the  J^-in. 


510 


DETAILS  OF  PRACTICAL  MINING 


holes  is  five  times  the  area  of  the  pipe.  The  capacity  of  the  pump  is 
1200  gal.  per  minute  or  600  gal.  for  each  side.  This  requires  a  velocity  of 
150  ft.  per  minute  in  the  suction  pipe,  and  of  30  ft.  per  minute  through 
the  J^-in.  holes.  It  is  good  practice  in  the  design  of  pump  suction  to  limit 
the  velocity  to  200  ft.  per  minute  and  to  make  it  less  than  that  if  the  pipe 
is  longer  than  25  ft.,  or  has  many  elbows. 


AIR  LIFTS 

Combination  Pump  and  Air  Lift  (Power). — An  extremely  ingenious 
method  of  connecting  an  air-actuated  mine  pump  is  illustrated  in  Fig. 
427.  The  device  was  installed  to  eliminate  freezing  troubles  in  the  ex- 
haust passages.  It  was  not  practicable  to  reheat  the  air;  so  the  connec- 
tions shown  in  the  illustrations  were  made.  The  pump  was  a  12  and 
6  X  13-in.  machine,  working  against  a  400-ft.  head  under  an  air  pressure 


PIG.    427. PUMP    EXHAUSTING    INTO    DISCHARGE    COLUMN. 

of  90  lb.  The  exhaust  was  piped  to  a  receiver  made  of  an  8-in.  by  4-ft. 
pipe.  A  connection  A  was  provided  for  exhausting  into  the  open  if  de- 
sired. The  receiver  was  connected  to  the  discharge  B  of  the  pump,  and 
in  this  connection,  a  check  valve  was  set  to  prevent  the  return  of  the 
water  to  the  air-end  of  the  pump.  The  air  working  in  the  pump  cylinder 
nonexpansively  left  the  cylinder  at  approximately  90  lb.  It  was  thus 
able  to  force  its  way  into  the  pump  column  provided  this  was  not  filled 
to  a  point  to  produce  a  head  greater  than  90  lb.  Once  mixed  with  the 
water,  the  air  acted  like  an  air  lift,  forming  a  mixture  in  the  pump  column 
much  lighter  than  water,  expanding  in  its  upward  course  and  assisting 
in  raising  the  water.  With  the  proportions  of  the  air  end,  the  water  end 
and  the  lift  here  given,  there  could  be  no  further  possibility  of  the  air  not 
being  able  to  exhaust  against  the  pressure  of  the  discharge  column. 

The  freezing  difficulty  was  effectually  overcome,  but  the  idea  would 
seem  to  be  capable  of  more  important  development.     A  mine  pump 


DRAINAGE  AND  VENTILATION 


511 


with  cylinder  ratios  designed  for  a  certain  lift  could  have  its  possible  lift 
thus  increased,  something  often  desirable  where  sinking  pumps  must  be 
adopted  for  station  work.  Furthermore,  a  permanent  installation  could 
be  designed  with  the  ratio  of  the  cylinder  diameters  so  adjusted  to  the 
lift  and  quantity  of  water  to  be  handled,  that  the  air  should  be  ex- 
hausted at  the  discharge  end  of  the  pump  column  at  atmospheric  pressure 
and  be  made  to  do  all  the  work  possible,  thus  utilizing  all  the  potential 
energy  in  the  compressed  air. 

Air  Lifts  for  Shaft  Unwatering  (By  Arthur  0.  Christensen). — A  shaft 
can  usually  be  unwatered  more  quickly  and  cheaply  with  an  air  lift  than 
with  pumps.  It  is,  therefore,  advisable,  before  allowing  a  mine  to  flood, 
to  connect  the  air  line  to  the  discharge  of  the  pump  line  as  near  the  bottom 


Pump  Discharge 


Pump 


=>A 

f'r  Line 
Air 

n 

n 

•      Hi        i^   ®\ 

I 

—  * 

1 

~i 
_ 

«&- 

Open    ML  , 


FIG.    428. — CONNECTIONS    FOR    AIR    LIFTS    UNDER   VARYING    CONDITIONS. 

of  the  shaft  as  possible,  preferably  a  few  feet  above  the  pump,  as  indicated 
in  Fig.  428.  If  there  is  a  tee  where  the  line  joins  the  pump  this  should  be 
left  open.  If  there  is  not  a  tee,  the  line  should  be  disconnected  from  the 
pump.  To  start  unwatering,  compressed  air  is  simply  turned  into  the 
air  line  and  the  pump-discharge  line  begins  to  work  as  an  air  lift.  The 
diameter  of  the  air  line  where  connected  to  the  water  pipe  should  be  about 
one-fourth  the  latter.  Even  if  the  pump  is  one  which  can  be  started 
while  drowned,  so  that  an  air-lift  attachment  seems  unnecessary,  still 
it  is  desirable  to  have  the  connection  made  as  described,  for  there  is  no 
knowing  how  long  the  pump  may  be  submerged  or  whether  it  will  work 
when  the  air  supply  is  turned  on.  In  such  a  case,  however,  it  is  not 
necessary  to  make  any  opening  in  the  discharge  line,  since,  if  the  air  lift  is 


512  DETAILS  OF  PRACTICAL  MINING 

to  operate  without  the  pump,  it  can  suck  water  through  the  pump  valves. 
Both  lift  and  pump  can  be  used,  one  helping  the  other.  The  air  lift  re- 
lieves the  pump  of  a  portion  of  its  work  by  diminishing  the  head  in  the 
discharge,  or,  looking  at  it  from  the  opposite  standpoint,  the  pump  aids 
the  lift  by  supplying  its  suction  end  with  water  at  a  pressure  which  may 
be  greater  and  cannot  be  less  than  would  be  the  case  were  the  pump  not 
to  act.  Conversely  if  it  is  found  that  a  pump  is  not  able  to  lift  its  water 
to  the  point  of  discharge,  the  suction  end  being  all  right,  a  small  amount 
of  air  admitted  to  the  discharge  line  just  above  the  pump  will  cause  it 
at  once  to  speed  up. 

In  most  cases,  however,  it  is  too  much  to  expect  a  retiring  manage- 
ment to  leave  a  mine  in  such  shape  that  it  is  necessary  only  to  start  up 
the  compressor  in  order  to  unwater  the  property.  The  question  is  how 
to  unwater  the  shaft  as  it  stands.  Frequently  there  is  a  pipe  line  run- 
ning straight  down  the  shaft.  Whether  the  bottom  of  this  be  open  or 
closed,  and  whether  there  be  a  pump  attached  or  not,  the  air  lift  can  be 
operated,  so  long  as  the  line  is  straight  enough  to  allow  a  pipe  to  be  run 
down  the  inside.  Fig.  428  represents  the  lower  end  of  the  inner  pipe. 
If  no  return  elbow  is  at  hand,  two  elbows  connected  by  a  close  nipple  will 
answer.  The  nozzle  is  made  by  heating  one  end  of  a  short  pipe  and  forg- 
ing it  down  to  about  three-fourths  or  one-half  its  original  diameter.  This 
arrangement  can  suck  water  through  a  drowned  pump,  although,  of  course, 
not  so  readily  as  if  there  were  no  such  obstruction.  Where  a  suitable 
pipe  is  in  the  shaft  but  is  closed  by  a  valve  or  otherwise,  a  charge  of 
dynamite  can  be  lowered  by  a  small  pipe  within  the  larger,  and  the  charge 
exploded  by  electricity — one  ordinary  dry  cell  will  set  off  an  exploder — 
thus  breaking  the  pipe.  The  saving  by  using  an  air  lift  for  the  job  is 
assumed  to  be  more  than  the  cost  of  repairs  to  the  pipe  line  later  on. 

In  case  no  suitable  pipe  for  the  water  discharge  is  found  in  the  shaft, 
a  simple  air  lift  can  be  dropped  down  a  vertical  shaft  or  can  be  lowered  in 
an  inclined  shaft  either  on  the  truck  or  simply  on  a  plank  laid  across  the 
rails.  A  2-in.  and  a  1-in.  line  make  a  convenient  size  for  such  a  lift,  as 
is  shown  in  Fig.  428.  At  intervals  of  from  15  to  30  ft.  the  two  lines  are 
strapped  together  as  indicated.  This  arrangement  will  operate  either 
vertically  or  on  an  incline.  As  soon  as  it  is  noticed  that  the  ratio  of  water 
to  air  being  discharged  has  decreased  considerably,  the  lift  must  be  sub- 
merged more,  or,  if  this  is  not  possible,  the  height  of  its  discharge  must 
be  diminished  by  installing  a  pump  as  near  the  water  as  possible  to  throw 
the  water  from  the  lift  to  the  surface.  With  100  Ib.  of  air  pressure,  such 
a  lift  as  indicated  can  raise  water  200  ft.  with  a  20-ft.  submergence,  or 
can  lift  50  ft.  with  almost  no  submergence  at  all.  The  air  issuing  from 
the  nozzle  serves  as  an  ejector  to  suck  up  and  carry  the  water  along  with 
it.  Air  lifts  can  be  compounded  to  raise  water  any  heights  with  any 


DRAINAGE  AND  VENTILATION 


513 


submergence,  down  to  almost  nothing,  but  in  general  a  pump  is  preferable 
to  such  a  complicated  arrangement. 

Six-inch  Pipe  for  Air-lift  Sump  (By  M.  J.  McGill). — While  sinking 
at  the  Silver  King  Consolidated,  trouble  was  had  from  a  small  flow  of 
water,  about  15  gal.  per  minute,  from  the  1100-ft.  station  and  about  one 
set  below.  Instead  of  installing  a  pump,  it  was  decided  to  rig  an  air  lift. 
The  water  had  to  be  pumped  to  a  winze  about  1800  ft.  in  from  the  shaft, 


\   o 


O         O      Q 


?o 


;o 


FIG.    429. CONSTRUCTION    OP   DOOR   AND    ARRANGEMENT    OF   VALVES. 

the  winze  collar  being  about  20.5  ft.  above  the  station  level.  In  the 
shaft  34  ft.  of  6-in.  pipe  was  hung  from  a  point  one  set  below  the  station 
and  blanked  at  the  lower  end  except  for  a  1-in.  drain  with  a  gate  valve. 
Within  4  in.  of  the  end  of  some  2-in.  pipe,  several  %-in.  holes  were 
drilled,  and  just  above  this  a  J^-in.  nipple  with  an  ell  on  each  end  was 
tapped  in.  In  the  outside  ell  a  ^-m.  pipe  was  screwed.  The  %-in. 
and  the  2-in.  pipes,  bound  together,  were  lowered  into  the  6-in.  pipe. 
The  J4-in.  was  connected  to  the  compressed-air  line,  compressor  pressure 

33 


514  DETAILS  OF  PRACTICAL  MINING 

being  100  Ib. ;  the  2-in.  pipe  was  connected  to  an  old  2-in.  air  line  which 
led  to  the  winze.  At  about  100  ft.  in  a  tee  was  put  in  on  the  2-in.  line 
and  a  valve  to  relieve  the  air  pockets.  The  flow  of  water  was  directed 
into  the  6-in.  pipe.  With  the  air-inlet  valve  open  about  one-sixth  of  a 
turn,  the  water  kept  about  14  in.  below  the  top  of  the  6-in.  pipe,  except 
when  the  miners  turned  on  the  air  to  blow  smoke  from  the  shaft  bottom. 

SEALING  OFF  WATER 

Built-up  Iron  Water  Door  (By  R.  R.  Heap).— The  draining  of  an  ore 
run  near  Miami,  Okla.,  involved  the  use  of  a  bulkhead  door  to  control  the 
flow  of  water  to  the  pump.  This  door  is  illustrated  in  Fig.  429.  The 
drainage  head  was  50  ft.,  and  the  door  was  built  to  withstand  a  pressure  in 
excess  of  requirements,  which  gave  it  extreme  solidity  of  construction. 
Its  width  and  height  were  determined  by  the  opening  necessary  for 
tramming  the  ore  to  the  shaft,  at  least  5  ft.  6  in.  in  height  and  4  ft.  in 
width.  The  Webb  City  and  Carterville  Foundry  &  Machine  Works  of 
Webb  City,  Mo.,  made  the  plans  and  built  the  door.  It  was  considered 
safest  to  regulate  the  volume  of  water  flowing  to  the  pump  by  means  of  a 
series  of  valves  in  the  door,  which  were  more  than  sufficient  in  total  area 
to  pass  the  entire  volume  of  water;  it  would  not  have  been  advisable  to 
regulate  the  volume  of  water  by  opening  the  door  to  any  required  width. 
The  drawings  show  the  construction  and  installation  so  clearly  as  to 
require  pointing  out  only  its  most  important  features. 

The  door  and  frame  were  installed  in  shale.  They  were  both  made  of 
heavy  boiler  iron  with  all  joints  securely  riveted  in  place.  The  contact 
joints  were  beveled  and  lined  with  a  metallic  packing.  To  insure  that 
the  setting  of  the  frame  should  be  watertight,  the  drift  at  the  point  of 
installation  was  enlarged  by  cutting  a  space  4  ft.  deep  and  4  ft.  wide  on 
both  sides  of  the  drift  in  the  floor  and  in  the  back  as  shown  in  Fig.  430. 
A  set  of  timbers  was  then  put  up,  to  which  the  frame  was  bolted  level,  and 
the  open  4-ft.  spaces  were  filled  in  with  a  rich  mixture  of  concrete,  flush 
with  the  top  of  the  sill,  with  the  insides  of  the  posts  and  with  the  bottom 
of  the  cap.  The  further  precaution  was  taken  of  extending  the  concrete 
filling,  flush  with  the  insides  of  the  timbers,  for  two  sets  in  front  and 
behind  the  door  frame.  The  trackway  through  the  door  was  made  in  a 
removable  section,  the  3  X  6-in.  ties  being  fitted  into  daps  cut  out  of  the 
sills,  so  as  to  make  a  close  joint  and  one  easily  and  quickly  removable. 

Two  6-in.  and  one  3-in.  iron  body,  brass  mounted,  wedge-pattern  gate 
valves  were  screwed  into  flanges  riveted  to  the  inside  of  the  door,  using 
nipples  just  long  enough  to  give  room  for  the  valve  wheels.  At  the  bot- 
tom a  slide  door  was  installed,  arranged  to  be  opened  and  closed  by  means 
of  a  heavy  air-drill  square-threaded  feed  screw  and  nut,  the  nut  tightened 


DRAINAGE  AND  VENTILATION 


515 


on  the  screw  by  a  %-in.  setscrew  and  held  in  place  in  a  slot  2%  in.  wide. 
The  drawing  shows  the  slide  door  tightly  closed.  Its  maximum  opening 
gives  a  space  6  X  12  in.,  more  than  sufficient  with  the  3-in.  valve  to  pass 
the  entire  flow  of  water. 


FIG.    430. DOOR   IN   DRIFT,    CONCRETE    LINING    AND    REMOVABLE    TRACK. 

The  door  was  held  tightly  closed  with  a  1-in.  turnbuckle  rod,  fastened 
with  an  eye-bolt  on  one  end  to  a  post  of  the  third  set  back  and  at  the  other 
end  to  the  door  with  a  heavy  clevis  of  1^-in.  round  iron.  This  clevis  was 


516 


DETAILS  OF  PRACTICAL  MINING 


fastened  to  the  door  at  one  of  the  upper  joints  by  a  %-in.  king  bolt  slipped 
through  the  eyes  in  the  clevis  and  the  %-in.  hole  in  the  door  joint.  With 
the  clevis  in  place  a  few  turns  of  the  turnbuckle  to  the  right  securely 
tightened  the  door;  a  few  turns  to  the  left  gave  ample  play  easily  to  pull 
out  the  clevis  bolt;  after  slipping  the  clevis  from  the  large  eye  in  the  end 
of  the  rod,  the  latter  would  swing  down  out  of  the  way  on  the  side  of  the 
drift  and  the  door  would  open.  An  offset  in  the  drift  allowed  the  door  to 
swing  back  out  of  the  way.  A  means  of  closing  the  door  from  the  surface 
was  also  provided;  a  small  %-in.  cable  was  fastened  to  the  door  at  the 
top  and  passed  through  two  eye-bolts,  one  on  the  side  of  the  drift  and  one 
at  the  corner  of  the  shaft.  On  the  surface  it  was  fastened  to  a  post  of  the 


1  Turned  BoHs 

FIG.  431. DOOR  AND  FRAME  TO  CONTROL  UNDERGROUND  WATER. 

headframe.  By  means  of  a  loop  in  this  cable  it  could  be  hooked  into  the 
hoisting  cable  snap-hook  and  tightened  with  the  hoist.  The  value  of 
such  a  door,  as  permitting  the  successful  use  of  a  single  pumping  unit,  is 
evident.  The  series  of  valves  is  of  great  importance  as  an  efficient  means 
for  regulating  the  flow  of  water  and  of  eliminating  the  danger  of  flooding 
the  pump,  which  might  occur  under  certain  conditions  were  the  size  of 
the  opening  of  the  door  itself  the  only  gage. 

Cast-iron  Door  for  Mine  Water  (By  H.  Beard). — Cast-iron  doors  to 
resist  the  pressure  of  water  underground  are  particularly  useful  in  control- 
ling the  flow  where  a  sudden  rush  of  water  is  expected  or  pumping  is 
interrupted  by  trouble  with  the  pump  or  with  the  power.  The  door  and 


DRAINAGE  AND  VENTILATION  517 

frame,  shown  on  the  left  and  right  respectively  of  Fig.  431,  were  designed 
for  use  by  the  Alvarado  Consolidated  Mines  Co.,  in  Parral.  One  in  use 
under  a  head  of  75  ft.  of  water  is  quite  tight  and  others  were  to  be  installed 
to  resist  heads  of  125  to  140  ft.  For  these  greater  heads  it  is  advisable  to 
reinforce  the  frame  with  stay-bolts  to  the  roof,  floor  and  walls  of  the  drift. 
It  is  estimated  that  the  door  will  resist  a  pressure  of  100  Ib.  per  square 
inch.  The  door  was  cast  at  the  local  foundry  in  one  piece,  the  frame  in 
two  pieces.  The  dimensions  are  as  shown  and  the  estimated  weight  is 
2640  Ib.  for  all  the  pieces.  The  pieces  of  the  frame  are  planed  where  the 
flanges  meet  and  are  bolted  together.  In  one  of  the  lower  corners  a 
round  flange  is  cast  on  with  a  6-in.  opening  for  water  discharge.  The  door 
is  self-sealing,  there  being  no  provision  for  holding  it  against  the  frame 
other  than  the  pressure  of  the  water.  For  this  purpose,  the  faces  of  both 
frame  and  door  are  planed,  and  a  J^-in.  groove  J^-in.  deep  is  planed  in  the 
face  of  the  door  to  take  J^-in.  square  canvas  packing.  To  enable  the  door 
to  come  to  a  proper  seating,  the  hinges  are  made  with  links  of  %-in. 
plate,  as  shown,  giving  some  play.  To  set  the  frame  in  the  drift,  a  small 
recess  in  the  rock  is  cut  on  all  four  sides  and  the  frame  held  in  this  with 
concrete.  In  cutting  this  recess,  great  care  should  be  taken  in  blasting 
and  all  loose  pieces  removed  in  order  to  prevent  leakage.  Sufficient  room 
should  also  be  cut  out  in  the  back  to  allow  the  concrete  to  be  easily 
tamped  into  place  on  the  top  of  the  frame. 

Concrete  Bulkhead  Under  200-lb.  Head  (Bull,  American  Institute  of 
Mining  Engineers). — At  the  Hibernia  magnetite  mine  in  New  Jersey,  it 
was  found  desirable  to  separate  the  old  workings  from  the  new  and  to 
allow  the  former  to  fill  with  water  to  the  850-ft.  level.  For  the  16th  level, 
a  truncated- wedge  dam  was  adopted.  The  pressure  side  of  the  dam  is  of 
greater  area  than  the  back,  so  that  the  resultant  action  is  similar  to  driv- 
ing the  wedge.  By  cutting  generous  skewbacks  in  the  walls,  roof  and 
floor,  this  becomes  in  reality  an  invisible  arch.  The  wedge  feature  tends 
to  compress  the  materials  in  the  bulkhead,  thereby  adding  to  its  imper- 
viousness.  Concrete  was  chosen  as  the  material.  To  lessen  the  labor 
and  simplify  form  construction,  straight  forms  were  placed  on  both  the 
front  and  back  of  the  dam,  making  the  arch  invisible.  As  ordinary  con- 
crete is  not  impervious  under  a  head  of  200  Ib.,  it  was  decided  to  water- 
proof the  concrete  by  facing  the  entire  pressure  side  with  a  3-in.  layer  of 
"Impervite,"  a  waterproofing  compound.  This  facing  was  carried  up 
with  the  concrete  to  insure  a  perfect  bond.  A  manway  through  the  dam 
was  provided  to  permit  inspection  or  repairs. 

The  relative  positions  of  an  old  bulkhead  and  the  new  bulkhead  are 
shown  in  Fig.  432.  The  old  bulkhead  leaked  to  the  extent  of  about  16  gal. 
per  minute.  The  five  pipes  through  it  permitted  pumping  to  the  surface 
the  water  from  behind  it.  The  new  bulkhead  was  designed  to  continue 


518 


DETAILS  OF  PRACTICAL  MINING 


DRAINAGE  AND  VENTILATION  519 

this  function  of  drainage  if  it  were  necessary,  and  hence  prolongations  of 
the  pipes  were  carried  through  it.  The  horizontal  rails  used  for  rein- 
forcement were  curved  to  the  radius  of  the  invisible  arch.  Great  care  was 
taken  thoroughly  to  coat  all  metal  surfaces  with  mortar.  A  manway 
pipe  was  provided  through  the  bulkhead.  It  was  decided  to  use  a  1:2:4 
mixture.  The  cement  was  Atlas  portland;  a  local  sand,  carrying  less 
than  3  per  cent,  of  foreign  matter,  was  obtained;  the  broken  stone  was  a 
gneiss,  the  result  of  former  milling  operations. 

In  drilling  the  recesses  for  the  bulkhead,  care  was  taken  to  point  the 
holes  so  that  the  excavation  would  coincide  with  the  design  in  form  and 
dimensions.  At  a  distance  of  25  ft.  from  the  old  dam,  holes  36  to  39  in. 
in  length  and  spaced  1  ft.  apart  were  drilled  in  the  sides,  roof  and  floor, 
at  right  angles  to  the  course  of  the  drift,  using  st oping  and  hand  drills. 
Thirty-five  feet  from  the  old  bulkhead,  a  series  of  holes  4  ft.  in  length  and 
from  1  to  1J^  ft.  apart  were  placed  slanting  to  conform  approximately 
with  the  inclinations  of  the  skewbacks.  These  holes  were  burdened  with 
only  about  1  ft.  of  ground.  Under  ordinary  conditions,  longer  holes 
would  have  been  drilled,  but  the  proximity  of  operating  pumps  made 
extraordinary  precautions  necessary  for  their  protection  during  the 
shooting.  A  group  of  six  holes  was  shot  at  a  time.  A  third  series  of 
holes  was  drilled  slanting  to  conform  with  the  deeper  portions  of  the 
recesses.  When  blasted,  this  series  broke  evenlya  t  the  line  of  the  3-ft. 
hole  first  drilled,  and  the  resultant  recess  conformed  almost  exactly  to 
the  figure  determined  upon,  while  the  total  excavation  agreed  with  the 
original  estimate  of  60  yd. 

The  materials  required  were  stored  close  to  the  shaft  collar.  Due  to 
the  lack  of  space  on  the  level,  the  matter  of  delivering  the  materials 
without  interrupting  work  was  troublesome.  Sand  and  stone  were 
sacked  on  the  surface.  The  empty  bags  produced  as  the  cement  was 
used  augmented  the  200  old  cement  bags  purchased  for  the  sacking.  A 
small  night  crew  lowered  much  of  the  material  required  for  the  next  day's 
work.  The  10  curved  rails  were  bent  on  the  surface  over  a  14-ft.  radius. 
The  bulkhead  forms  were  built  of  2-in.  undressed  lumber,  with  6-  to  10-in. 
round  posts  for  studding  and  braces.  The  forms  were  thoroughly  braced 
and  were  wired  to  stiffen  them.  The  interior  faces  of  the  forms  were 
covered  with  tar  paper,  and  the  junction  of  the  forms  with  the  rock  was 
plastered  with  a  1 : 1  cement  mortar  on  all  sides.  The  pressure-  side  forms 
were  carried  to  the  roof  of  the  level  at  once,  but  did  not  extend  into  the 
recess.  The  recess  was  thoroughly  cleaned  of  loose  rock  and  washed 
down,  and  all  the  reinforcing  material,  the  pipes  and  the  manway  were 
placed  in  position  before  the  concreting  was  started.  The  floor  and  sides 
of  the  recess  were  plastered  with  a  1 ;  1  cement  mortar  before  placing  the 
concrete. 


520  DETAILS  OF  PRACTICAL  MINING 

A  batch  of  concrete  contained  %  cu.  yd.  The  sand  was  first  placed  on 
the  mixing  platform  and  the  heaps  flattened  down.  On  this  was  emptied 
the  cement,  and  these  two  materials  were  thoroughly  mixed  and  flattened 
out  before  receiving  the  stone.  This  mixing  took  place  about  12  ft.  from 
the  front  form  of  the  bulkhead.  Enough  water  was  used  to  make  a  wet 
mixture.  Two  men  did  the  first  mixing  and  turned  the  mass,  then  passed 
it  on  to  the  next  two,  who  again  turned  it,  passing  the  finished  concrete 
to  the  last  two  men  at  the  mixing  board.  These  men  shoveled  directly 
into  the  form.  In  this  manner,  while  each  two  men  received  a  short  rest 
of  a  few  minutes  between  batches,  fresh  material  was  being  placed  on  the 
starting  end  of  the  mixing  platform  while  the  men  nearest  the  form  were 
still  disposing  of  the  concrete  mixture.  This  also  insured  a  thorough 
mixing.  One  man  remained  in  the  form  to  level  off  each  batch.  The 
best  day's  work  consisted  of  placing  12  yd.  of  concrete.  The  water- 
proofing compound  was  carried  up  as  a  3-in.  facing,  level  with  the  concrete. 
An  even  thickness  of  the  waterproof  layer  was  maintained  by  the  use  of 
three  forms  of  a  %4-in.  plate,  6  ft.  long  by  6  in.  wide,  fitted  at  the  upper 
corner  with  3-in.  spreading  bolts.  These  forms,  placed  across  the  entire 
width  of  the  face,  were  raised  3  to  4  in.  at  a  time,  and  enough  concrete  was 
then  shoveled  against  them  to  keep  them  in  place.  The  almost  semi- 
liquid  waterproofing  compound  was  mixed  on  the  level  and  was  carried 
to  the  forms  in  buckets.  Before  leaving  at  night,  sharp  stones  of  about 
100  Ib.  weight  were  set  at  least  6  in.  apart  in  the  concrete  mass.  This 
made  a  strong  bond,  and  before  concreting  the  next  day,  this  rough 
surface  was  freshly  plastered  with  a  thin  1 : 1  mortar.  As  the  roof  was 
reached,  false  forms  were  placed,  and  the  work  was  finally  finished  in 
tightly  bonded  dovetailed  blocks.  Throughout  the  work,  the  leakage 
from  the  old  dam  passed  through  the  2-in.  drain  pipe  of  the  bulkhead. 

Seven  2-in.  grout  pipes,  four  on  the  pressure  side  and  three  on  the 
opposite  side,  were  placed  in  the  concrete  as  the  work  neared  completion. 
They  were  all  placed  near  the  roof  and  directed  to  the  places  most  diffi- 
cult to  fill  with  concrete.  As  the  work  had  to  be  hurried,  but  a  day  and 
a  half  elapsed  after  completion  of  the  cement  work  before  grouting  was 
begun.  The  grout  consisted  of  one  and  one-half  parts  of  sand  to  one  part 
of  cement  made  fluid  with  water-dissolved  "Impervite."  A  mine-made 
grout  gun  was  used  and  the  grout  was  forced  successively  into  the  several 
pipes  by  means  of  air  under  the  pressure  of  85  Ib.  per  square  inch.  When 
the  grout  was  forced  through  the  different  pipes,  its  ejection  through  the 
other  pipes  indicated  that  the  greater  voids  were  filled.  As  the  gun  con- 
nections were  changed,  those  pipes  giving  the  greatest  discharge  were 
plugged,  and  the  discharge  was  finally  limited  to  one  pipe.  This,  too, 
was  filled  and  plugged.  The  first  day's  grouting  was  allowed  .to  set  over 
night,  and  the  following  day  all  the  pipes  were  again  tested.  This  time 


DRAINAGE  AND  VENTILATION 


521 


there  was  no  communication  between  the  pipes,  and  as  little  or  no  grout 
could  be  forced  into  any  one  of  the  pipes,  the  grouting  was  considered 
most  satisfactory.  For  three  weeks  the  new  bulkhead  did  not  receive 
any  load.  During  this  time  the  2-in.  drain  pipe  was  left  open.  The 
bulkhead  was  tested  by  pumping  water  up  to  the  pressure  of  160  Ib. 
into  the  space  between  the  old  and  the  new  bulkheads  through  the  2-in. 
drain  pipe.  The  results  were  entirely  satisfactory;  the  total  seepage 
amounted  to  only  J£  gal.  per  minute  at  first,  and  this  small  leakage  sub- 
sequently stopped  almost  completely. 

A  cheap  class  of  labor  was  employed  exclusively,  the  men  receiving 
$2  per  10-hr,  shift.  Following  is  a  table  showing  the  cost  of  the  work. 
The  interference  caused  by  the  necessity  of  keeping  two  large  pumps  in 
operation  within  50  ft.  of  the  bulkhead  was  perhaps  the  greatest  cause 
for  the  high  cost.  The  labor  cost  of  lowering  materials  was  also  high. 

SUMMARY  OF  COSTS 


Total 

Per  cu.  yd. 

Labor  

$790.00 

$13.17 

Superintendence  

130.00 

2.17 

Transportation 

50  46 

0  84 

Materials.    .  .         .  .    .                        

503.88 

8  38 

Totals 

$1474  34 

$24  56 

Plugging  Water  Channels  into  Mine  (By  J.  E.  Reno).— The  Little 
Mary  mine  is  situated  on  a  flood  plain  of  the  North  Fork  of  Spring  River, 
3  miles  northwest  of  Neck  City,"  Jasper  County,  Mo.  The  mill  was 
erected  and  started  to  operate  in  the  summer  of  1910;  mining  was  carried 
on  successfully  until  some  time  in  March,  1911,  when  the  river,  through 
sink  holes  in  its  bottom  and  a  solution  channel  following  the  contact  of 
the  shale  and  limestone  as  indicated  on  the  map,  Fig.  433,  broke  into  the 
mine  workings.  The  water  came  into  the  workings  from  all  sides  and 
its  volume  was  so  great  that  the  mine  was  flooded  and  work  had  to  be 
abandoned  until  the  high  water  in  the  river  subsided,  when  various 
schemes  for  stopping  up  the  sink  holes  were  tried.  A  drought  of  about 
four  months'  duration  followed  the  wet  period  and  while  the  river  was 
extremely  low  coffer-dams  of  burlap  sacks  filled  with  soil  from  the  river 
bank  were  built  around  the  sink  holes.  The  holes  were  then  filled  with 
hay  and  dirt  and  covered  with  boulders.  During  this  time,  June  1  to  17, 
the  mine  was  dewatered.  The  channel  had  still  not  been  closed,  since 
muddy  water  came  into  the  mine,  and  it  was  evident  that  dirt  was  not 
the  material  with  which  to  choke  off  the  water.  It  was  next  attempted 
to  seal  the  sink  holes  with  rock  and  concrete,  but  in  August  when  another 


522 


DETAILS  OF  PRACTICAL  MINING 


flood  came,  new  sink  holes  developed  and  the  water  flow  into  the  mine 
for  about  two  months  was  as  heavy  as  ever.  In  the  meantime  more 
pumps  were  installed,  capable  of  handling  the  water,  which  had  increased 
from  700  to  about  3000  gal.  per  minute.  For  two  weeks  more  the  former 
methods  were  tried  at  a  further  cost  of  $1000,  but  without  success. 

The  plan  was  then  devised  of  running  a  tailing  flume  from  the  mill 
to  the  river,  a  distance  of  600  ft.,  and  extending  it  to  the  various  sink 
holes.  This  cost  $600  but  did  away  with  carting  the  tailings.  The 
tailings  contained  a  good  deal  of  cementing  material  and  were  found  to  be 
a  cheap  and  efficient  material  both  for  the  coffer-dams  and  for  filling  the 


PIG.    433. MAP    SHOWING    RELATION    BETWEEN    RIVER    AND    MINE. 

sink  holes.  In  two  hours  after  the  tailings  had  been  turned  into  the 
holes  the  water  had  been  cut  down  to  the  normal  flow  of  700  gal.  per 
minute.  When  nearly  filled,  boulders  were  piled  on  the  tailings  up  to  the 
level  of  the  bottom  of  the  river  to  serve  as  ballast  and  keep  the  river  from 
washing  out  the  tailings.  Three  other  breaks  in  the  river  at  different 
periods  were  stopped  in  the  same  manner,  and  the  river  permanently 
choked  off. 

VENTILATING  DEVICES 

Pressure  Ventilation  in  Cripple  Creek  (By  S.  A.  Worcester). — The 
pressure  system  of  ventilation  consists  of  simply  sealing  or  bulkheading 
the  mine  practically  air-tight  and  forcing  in  air  under  what  pressure  is 


DRAINAGE  AND  VENTILATION 


523 


necessary  to  expel  mine  gas  through  a  fissured  formation.  Low  pressures 
only  are  used,  up  to  3  oz.  per  square  inch  and  are  obtained  by  means  of 
a  jet  or  a  fan.  The  pressure  system  is  applied  in  the  Cripple  Creek  dis- 
trict where  many  of  the  mines  are  seriously  affected  by  the  escape  of  gas, 
consisting  largely  of  CC>2,  from  the  rocks. 

Some  ingenuity  and  care  are  required  in  selecting  the  point  of  installa- 
tion for  the  fan  or  jet  and  in  shutting  off  free  escape  of  the  air  through  mine 
workings.  Thus  at  the  Conundrum  mine,  a  short  drift  GHT,  Fig.  434, 
connecting  the  main  shaft  with  the  Gold  Hill  tunnel,  was  first  selected 
for  the  fan.  It  was  found,  however,  that  gas  issued  from  the  Gold  Hill 
tunnel  and  mixed  with  the  air  which  was  being  forced  into  the  mine. 
The  fan  was  therefore  moved  to  a  chamber  EB  cut  in  the  Conundrum 


CONUNDRUM 
PIG.    434. — PRESSURE  VENTILATION  IN  SEVERAL  CONNECTED  MINES. 

adit  at  the  entrance  bulkhead.  This  fan  has  a  56-in.  blast  wheel,  a  30- 
sq.  in.  discharge  opening,  runs  at  340  r.p.m.,  is  driven  by  a  15-hp.  motor 
and  operates  for  about  eight  and  one-half  hours  daily.  In  the  Midget 
mine  a  set  of  doors  was  first  placed  in  the  vertical  shaft  at  Z>,  20  ft.  below 
the  shaft  mouth  and  the  manway  MW  was  lined  with  1-in.  boards  bat- 
tened with  canton  flannel  soaked  in  P.  &  B .  paint.  This  made  a  wind  trunk 
from  the  blower  through  the  door  frame  bulkhead.  The  air  was  found 
to  short-circuit  through  old  stopes,  which  could  not  easily  be  shut  off. 
Therefore  the  fan  was  moved  to  D2  and  the  wind  trunk  extended  to  that 
point.  The  fan  F  is  a  converted  steel-plate  exhauster  with  one  side  inlet 
and  is  set  directly  over  the  manway.  It  has  a  66-in.  blast  wheel  and 
a  36-sq.  in.  discharge;  it  is  driven  at  400  r.p.m.  by  a  20-hp.  motor. 


524  DETAILS  OF  PRACTICAL  MINING 

At  the  Conundrum  mine  two  worked -out  stopes  partly  filled  with  fine 
rock  connected  with  the  Midget.  The  air  passed  freely  through  these, 
and  the  bulkheads  A  and  B  did  not  stop  leakage  to  the  Midget.  Calking 
with  oakum  between  the  round  lagging  at  C  and  D  did  not  stop  the  leak- 
age although  it  absorbed  much  P.  &  B.  paint.  Finally  the  entire  front 
of  these  stopes  at  C  and  D,  a  distance  of  about  70  ft.,  was  boarded  over 
with  1-in.  dressed  boards,  fitted  carefully  to  the  foot  and  hanging  walls 
and  battened  with  canton  flannel  strips  well  soaked  in  P.  &  B.  paint. 
This  made  them  practically  air-tight.  Where  a  level  connects  directly 
from  one  mine  to  the  other,  as  at  SB,  a  permanent  bulkhead  of  1-in. 
lumber  is  built,  with  the  dressed  side  toward  the  pressure  and  two  3X8- 
in.  girts  behind,  securely  wedged  in  hitches.  All  loose  rock  is  cleared 
away  at  the  top,  sides,  and  bottom  down  to  solid,  and  swept  clean. 
Boards, are  nailed  upright  and  trimmed  so  as  to  fit  closely  the  irregular 
rock  surface.  The  rocks  and  the  board  are  painted,  and  the  canton- 
flannel  strip  painted  on  both  sides  is  stuck  over  the  crack  and  again 
painted.  Nothing  else  equals  P.  &  B.  paint  for  this  purpose.  A  door- 
way 20  X  24  in.  is  cut  about  18  in.  above  the  level;  a  trap  door,  23  X  27 
in.,  covers  this  opening.  It  must  not  fit  between  strips  edgewise,  or 
moisture  might  make  it  bind.  It  must  lie  flat  against  the  bulkhead, 
with  four  thicknesses  of  canton  flannel,  nap  side  out,  tacked  on  in  strips 
1^2  m-  wide  around  the  edges  where  it  rests  on  the  bulkhead.  A  cheap 
door  may  be  made  without  hinges  and  merely  held  by  two  buttons. 
This  permits  the  passage  of  a  man  for  the  purpose  of  inspecting  the 
bulkhead  with  a  candle.  A  slight  leak,  when  pressure  is  on,  will  give 
current  enough  to  deflect  a  candle  flame.  Where  a  worked  out  stope, 
LS,  partly  filled  with  waste  was  found,  passing  from  one  property  into 
the  other,  and  where  a  bulkhead  at  the  property  line  would  be  expensive, 
the  stope,  since  it  had  no  value,  was  simply  shut  off  by  placing  a  perma- 
nent bulkhead,  LB,  on  the  level.  Leasers  having  ground  which  they 
desired  to  work  in  an  adjoining  mine,  at  FS,  arranged  with  the  Midget 
to  ventilate  their  workings  by  placing  a  bulkhead  at  FB. 

Fig.  435  shows  the  details  of  an  entrance  bulkhead  for  tunnels  or 
drifts  using  an  air-jet  injector  of  crude  form  for  supplying  air.  To 
erect  it,  proceed  as  follows:  Select  a  place  in  solid  ground,  free  from  cracks 
or  open  fissures,  and  clean  away  all  loose  rock  at  the  bottom,  down  to  the 
solid,  sweeping  clean  at  the  bottom,  sides,  and  top.  Set  the  3  X  10-in. 
door  posts  1,  wedging  them  solidly  in  hitches,  with  the  cap  2  spiked  be- 
tween them.  Nail  1-in.  boards  on  the  front  and  back  of  the  posts  to  a 
height  within  J^  in.  of  the  plate  3.  Nail  1-in.  boards  horizontally  on  the 
front  side  of  the  posts  and  cap  up  to  the  top  of  the  drift,  trimming  with  a 
compass-saw  the  ends  next  to  the  rock  to  fit  the  rough  surface  closely, 
leaving  no  opening  wider  than  ^-in.  Make  a  1:5  cement  mortar -with 


DRAINAGE  AND  VENTILATION 


525 


about  enough  water  to  show  on  top  after  the  mortar  has  settled  a  short 
time.  Fill  the  bottom  of  the  bulkhead  to  the  height  of  the  plate  3, 
which  should  be  leveled,  embedding  many  large  clean  rocks  in  the  mortar, 
but  taking  care  that  they  do  not  touch  the  form,  as  that  causes  voids. 
Embed  the  plate  in  wet  mortar,  tamping  concrete  under  the  edge  at  4. 
The  plate  is  usually  24  X  M  X  36  in.,  and  must  fit  closely  between  the 
posts.  After  the  bottom  is  filled,  nail  1-in.  boards  singly,  smooth  side 
out,  on  the  inside  of  the  frame,  filling  with  mortar  and  rock  as  each  piece  is 
nailed,  and  making  sure  that  no  voids  are  left.  As  the  height  increases 
the  pressure  of  f mortar  on  the  lower  boards  increases,  and  if  the  drift  or 
tunnel  is  large,  making  these  boards  long,  it  will  be  necessary  either  to 
brace  the  unsupported  ends  or,  better  still,  to  run  wires  through  from  one 
side  to  the  other,  to  prevent  bulging.  When  approaching  the  top  of  the 


FIG.    435. — AIR-TIGHT     DOOR     AND     AIR     INJECTOR. 

bulkhead,  the  mortar  is  made  drier,  and  only  small  rocks,  if  any,  are  used 
in  order  to  make  a  good  joint  and  prevent  undue  shrinkage  in  drying. 
The  edges  where  the  bulkhead  joins  the  rock  should  be  gone  over  with 
clear  cement  when  the  bulkhead  has  set  four  or  five  days,  and  all  shrinkage 
cracks  closed,  particularly  around  the  top,  where  there  is  usually  some 
settling.  The  door,  6,  is  made  of  two  thicknesses  of  1-in.  clear-pine 
dressed  boards.  Two  thicknesses  of  the  heaviest  canton  flannel  are 
placed  between  the  boards  and  2-in.  nails  are  used  close  together  and 
clinched  on  the  pressure  side.  The  boards  next  to  the  door  frame  are 
horizontal.  To  prevent  twisting,  the  door  should  be  nailed  together  on 
leveled  horses  or  supports. 

Care  must  also  be  taken  in  setting  the  bulkhead  posts  to  have  them 
" out  of  wind."     The  door  must  not  fit  between  strips  or  in  the  frame,  but 


526  DETAILS  OF  PRACTICAL  MINING 

must  lie  flat  on  the  bulkhead.  The  door  laps  the  opening  1J^  in.  at  the 
top  and  sides,  and  a  canton-flannel  strip  of  four  thicknesses,  1^  in.  wide, 
is  tacked  around  the  door  at  9,  where  it  closes  against  the  1-in.  facing  10. 
A  5-in.  4-thick  strip  is  doubled  around  the  bottom  edge  of  the  door  and 
tacked  on  both  sides.  All  of  these  strips  are  laid  with  the  nap  outward 
and  fastened  with  carpet  tacks  spaced  about  1  in.  apart.  The  track  rails 
are  cut  off  and  the  ends  tapered  down  and  curved  so  as  to  form  horns, 
which  rest  on  the  plate,  clearing  the  door.  The  bulkhead  is  inclined 
1  in.  per  foot,  so  that  the  door  swings  clear  of  the  plate  and  rails  when 
opening.  Ten-inch  T-hinges  are  screwed  to  the  door  and  to  blocks  5, 
which  are  of  the  same  thickness  as -the  door  screwed  to  the  bulkhead. 
The  pressure  gage  7,  a  glass  U-tube,  is  placed  at  a  convenient  height  on 
the  outside  of  the  bulkhead  and  connected  by  a  short  rubber  tube  8  with  a 
nipple  passing  through  the  bulkhead.  The  glass  tube  is  half  filled  with 
kerosene.  If  it  is  less  than  J£  m-  inside  diameter,  capillarity  will  impede 
its  action.  It  is  well  to  keep  this  pressure  gage  in  good  order,  because  it 
indicates  any  failure  of  pressure,  with  the  accompanying  danger  from  gas. 

The  air  jet  or  injector,  Fig.  435,  includes  a  short  8-in.  galvanized  pipe 
A,  into  which  the  1-in.  compressed-air  pipe  B  projects  a  short  distance. 
Usually  it  is  well  to  have  at  hand  three  different  pipe  caps,  PC,  with  ori- 
fices about  %2  in.,  Jfe  in.  and  %6  in.  diameter.  The  smallest  may  be 
used  for  ventilating  small  workings  or  in  good  weather,  and  the  others  for 
heavier  demands.  The  M2-in.  jet  seems  to  use  about  as  much  air  as  one 
hammer  drill.  A  check  valve,  CV,  of  light  tin  is  held  by  the  small  strap 
hinge,  SH,  anc  has  four  thicknesses  of  canton  flannel  held  by  its  turned 
edge,  making  a  good  joint  with  the  wired  edge  of  the  pipe  A.  The  cross- 
bar CB  and  the  clamp  C  supporting  the  1-in.  pipe  centrally  are  made  of 
1  X  M 6~in.  bar,  with  J^-in.  stove  bolts.  The  circular  jet  orifices  are 
reamed  as  shown  full  size  at  K,  giving  a  spreading  discharge  to  the 
compressed  air.  Any  tinner  can  make  this  air-jet  outfit  in  a  short  time, 
and  at  small  cost .  This  device  is  only  recommended  for  temporary  use  of 
where  compressed  air  is  cheap. 

A  fan  electrically  driven  is  a  more  economical  arrangement  in  most 
cases,  especially  where  large  volumes  of  air  are  needed.  The  check  valve 
CV  may  be  hung  up,  so  as  not  to  impede  the  air  current  during  the  shift, 
but  is  dropped  to  its  seat  when  the  jet  is  shut  off  and  the  door  is  left 
closed,  with  the  effect  of  impeding  appreciably  the  entrance  of  mine  gas  to 
the  workings.  The  end  of  the  pipe  A  is  inclined  so  that  the  check  valve 
shuts  by  gravity. 

The  doors  used  at  the  Midget  vertical  shaft,  where  a  skip  is  used  for 
hoisting,  are  made  of  double  2-in.  clear  pine,  with  two  thicknesses  of  can- 
ton flannel  between,  and  have  forged  hinges.  They  are  notched  to  clear 
the  guides  and  have  all  seating  or  meeting  edges  stripped  with  four  thick- 


DRAINAGE  AND  VENTILATION 


527 


nesses  of  flannel,  tacked  closely,  nap  side  out.  The  rod  R,  Fig.  436,  with 
the  links  L,  opens  and  closes  the  doors  together.  The  spring  S  assists  in 
starting  the  doors  from  the  vertical  position  toward  closing,  and  the  steel 
bell-cord  BC  passes  up  the  shaft,  over  a  sheave  to  the  lever  L  with  ful- 
crum at  F,  and  is  placed  within  easy  reach  of  the  hoist  engineer.  The 
weight  W  nearly  balances  the  doors  and  spring.  The  parts  are  held 
in  the  open  or  closed  position  by  hooking  the  lever  L  over  the  stationary 
block  B.  The  weight  of  these  doors  and  connections  is  sufficient  to 


ELEVATION 

FIG.    436. DOOR     ARRANGEMENT     IN     MIDGET     SHAFT. 

resist  the  pressure  used  at  this  mine.  The  rope  guide  RG  is  bolted  to 
the  door  and  is  easily  renewable  when  worn.  It  directs  the  rope  into 
the  center  groove  when  the  doors  are  closed,  preventing  it  from  catching 
between  the  meeting  edges. 

When  installing  shaft  doors  at  the  Little  Nell  mine,  Fig.  437,  a  place 
was  chosen  in  solid  rock  15  ft.  below  the  shaft  collar,  and  enough  of  the 
shaft  timbering  was  removed  to  make  room  for  the  frame  A  and  for 
swinging  the  doors  B  clear  of  the  shaft.  The  rock  was  swept  clean  on 
all  sides,  to  give  a  good  joint  for  concrete.  The  sides  of  the  frame  A 


528 


DETAILS  OF  PRACTICAL  MINING 


extend  through  the  man  way,  giving  sills  for  the  bulkhead  of  1-in.  boards. 
The  cracks  are  battened  with  the  heaviest  canton  flannel,  well  soaked 
and  stuck  on  the  freshly  painted  surface  with  P.  &  B.  paint,  then  painted 
on  the  back.  The  frame  A,  being  firmly  wedged  in  place  and  leveled,  is 
concreted  all  around,  using  the  mortar  described  in  the  foregoing.  Many 
large  clean  rocks  are  embedded  in  the  mortar,  taking  care  to  leave  no 
voids  and  making  the  top  about  2  in.  of  clear  mortar,  with  no  rocks. 
The  doors  B  are  made  of  1-in.  clear  dressed  boards,  crossed,  with  two 
thicknesses  of  canton  flannel  between  and  2-in.  clinched  nails  spaced 
closely.  They  should  be  free  from  twist  and  lie  flat  on  the  frame.  The 
frame  should  be  dressed  where  the  doors  seat.  Canton-flannel  strips  FS, 
about  1%  in.  wide,  in  four  thicknesses,  are  tacked  around  the  three  edges 
of  the  doors  where  they  rest  on  the  frame  and  on  the  under  side  of  the 


FIG.    437. — DOOR     IN     LITTLE     NELL     SHAFT. 

batten  strip  BS.  The  doors  are  notched  at  the  center  to  fit  the  hoisting 
rope  nicely,  and  the  rope  guide  RG,  of  hard  pine,  is  screwed  to  the  door. 
The  lower  boards  run  lengthwise.  Ten-inch  T-hinges  are  used.  The 
weights  WWj  in  this  case  worn-out  sheave-wheels,  were  determined  by 
experiment  after  pressure  on  the  door,  and  are  bolted  to  the  door.  The 
batten  strip  is  fast  to  the  door  having  the  rope  guide,  and  this  door  must 
be  opened  first  and  closed  last  to  prevent  interference.  Cotton  bell-cords 
BC  are  fastened  to  staples  near  the  edges  of  the  doors  and  are  led  by 
pulleys  to  handles  with  hooks  within  easy  reach  of  the  engineer.  The 
doors  must  not  fit  edgewise  but  lie  flat,  or  moisture  will  make  them  trouble- 
some. 

Many  fixed  bulkheads  have  been  built  in  shafts  and  raises  by  simply 
stulling  and  lagging  the  opening  and  packing  a  few  inches  of  black  surface 


DRAINAGE  AND  VENTILATION  529 

soil  on  top  of  the  lagging.  Ordinary  mine  rock,  however  fine,  seems  to 
leak  very  much,  but  black  surface  soil  makes  an  air-tight  stopping  when 
well  packed. 

Automatic  Door  for  Ventilation  Control  (By  H.  S.  Gieser). — At  the 
Jupiter,  which  is  one  of  the  deep-level  mines  in  the  Germiston  area  of  the 
East  Rand,  there  are  two  shafts,  the  Howard  and  the  Catlin,  both  of 
which  are  part  vertical  and  part  inclined.  The  bottom  of  the  Catlin  is 
5040  ft.  vertically  below  the  surface  and  at  these  great  depths  the  heat 
is  excessive.  Mechanical  ventilation  is  employed  and  ttf  guide  the  air 
through  the  stopes,  automatically  operated  doors  are  provided  on  the 
levels,  approximately  as  shown  in  Fig.  438.  The  sliding  door  is  made  in 
two  leaves  A,  which  slide  laterally  by  means  of  the  sheaves  B  on  the  1-in. 
inclined  round  irons  C.  The  doors  are  made  of  a  layer  of  1-in.  vertical 
boards  and  a  layer  IJ^-in.  horizontal  boards  and  are  of  the  dimensions 
shown.  The  sheaves  are  6  in.  in  diameter  and  carry  the  doors  by  iron 
straps  D,  3  X  28  in.  The  round  irons  are  carried  on  timber  pieces  E, 
3  X  3  in.  by  4  ft.  3  in.,  inclined  from  the  center  of  the  drift  at  an  angle 
of  10°.  As  the  doors  are  forced  open,  the  sheaves  roll  out  and  up  on  the 
round  irons  against  gravity  and,  when  released  again  by  the  passage  of 
the  car,  they  slide  together  by  their  own  weight. 

The  doors  are  actuated  by  the  four  angle  irons  F,  set  two  on  each  side 
so  that  cars  from  either  direction  will  open  the  doors.  Each  angle  has 
one  end  pivoted  on  the  inner  edge  of  the  door  at  G,  and  the  other  end 
slotted  and  moving  on  a  fixed  pin  at  H.  They  are  set  at  a  height  to 
catch  a  car  body,  and  on  each  side  of  the  door  one  rail  is  slightly  higher 
than  the  other.  The  car  entering  between  them  forces  them  apart  and 
opens  the  doors,  and  as  it  passes,  allows  them  to  close  in  a  similar  manner. 
The  angles  are  2%  X  2J^  in.  and  are  10  ft.  long,  set  with  one  outer  side 
up  and  one  toward  the  center  of  the  drift.  The  slot  at  H  is  %  X  4^ 
in.  The  drift,  approximately  7  ft.  wide,  is  closed  for  the  most  part 
by  a  1-in.  wood  brattice  /,  only  enough  opening,  3  ft.  4  in.,  being  left 
for  the  door  to  cover,  as  will  admit  a  car.  This  opening  is  contained  in 
a  frame  of  6  X  6-in.  stuff  J,  to  which,  as  well  as  to  slanting  3  X  6-in. 
pieces  K,  the  1-in.  brattice  is  fastened.  The  pins  on  which  the  angles 
slide  are  carried  by  a  frame  L  of  6  X  6-in.  material. 

Ventilating  Pipes. — A  useful  novelty  in  ventilating  equipment, 
especially  adapted  to  the  wide  connecting  drives,  raises  and  winzes  of  the 
district,  is  described  by  H.  Bottomly  in  an  annual  report  of  the  Depart- 
ment of  Mines  and  Industries  of  South  Africa.  The  device  consists  of 
J^-in.  steel  plates,  6  X  4  ft.,  bent  to  U-shapes,  18  in.  across  and  18  in. 
deep.  The  sections  are  inverted  and  laid  on  the  floor  of  the  drive,  loose 
ground  being  placed  against  the  contact  with  the  rock  to  insure  a  tight 
joint.  Sections  are  machine  rolled  and  are  capable  of  being  bolted  to- 

34 


530 


DETAILS  OF  PRACTICAL  MINING 


'  'V^^CV^WOS?  SECTION  OF  mxny^f^-  I't     ' 

~'   t>   -$,&  &&rp?*7jf-/*<r  ^/^/-/     ' 


BOTTOM  VIEW  OF^RRAN6tMENT  IN  DRIFT 
PIG.    438. — DOOR    TO    CONTROL   VENTILATION    THROUGH    DRIFT. 


DRAINAGE  AND  VENTILATION 


531 


gether  in  a  tight  joint,  assisted  by  a  gasket  of  tarred  cloth.  Area  available 
in  these  pipes  is  2  sq.  ft.,  which  is  far  superior  to  the  10-in.  galvanized-iron 
pipes  in  common  use,  and  their  comparative  immunity  from  damage 
places  them  above  anything  else  in  use  for  the  purpose  at  the  present  time. 
The  manager  of  the  State  Mines,  Graham  Bell,  the  inventor  of  the  sys- 
tem, has  tried  galvanized-iron  pipes  at  lOd.  per  foot,  and  corrugated-iron 
bratticing  along  the  main  connection  drives  at  a  cost  of  5s.  per  foot,  but 
has  given  both  up  for  the  steel  pipes  now  in  use,  which  cost  3s.  7d.  per 
running  foot  and  require  practically  no  maintenance. 

Tunnel  and  Level  Ventilation. — The  ventilation  of  workings  reached 
through  long  tunnels  can  probably  be  accomplished  by  no  simpler 
means  than  that  employed  in  one  of  the  older  Mexican  mines.  This  mine 
was  worked  through  a  tunnel  over  a  mile  long.  To  establish  a  system  of 


FIG.    439. STOVE  FOR  SUCKING  GASES  FROM  TUNNEL. 

ventilation  for  reaching  the  workings  inside,  a  deep  channel  was  cut  in  the 
floor  of  the  tunnel,  and  this  channel  was  covered  with  flat  stone,  or  loza, 
set  in  cement.  In  this  way  the  water  conduit  was  made  to  serve  also  as  an 
airway.  The  water  flow  assisted  in  drawing  out  the  air.  Issuing  from 
the  tunnel  the  water  conduit  was  connected  with  a  length  of  nearly 
vertical  pipe  down  which  the  water  ran,  acting  as  an  aspirator  and  setting 
up  a  good  circulation  of  air  in  the  mine. 

Adobe  Stove  for  Tunnel  Ventilation  (By  T.  Swift). — Fig.  439  shows  a 
modification  of  the  stove  ventilator,  as  used  in  Mexico.  This  stove  was 
built  of  adobe  bricks  and  was  rather  large,  4  X  4  ft.  square,  5  ft.  high, 
with  a  stack  10  ft.  high.  It  was  built  outside  of  the  tunnel  and  above  the 
portal.  The  air  pipe  was  run  from  the  last  set  of  timber  near  the  face 
of  the  tunnel  and  entered  the  stove  at  the  top  of  the  hearth.  A  roaring 
wood  fire  would  suck  the  powder  smoke  from  the  400-ft.  tunnel  after 


532 


DETAILS  OF  PRACTICAL  MINING 


shooting,  in  10  or  15  min.  The  arrangement  seems  to  require  only  that 
the  top  of  the  hearth,  where  the  pipe  enters,  be  above  the  elevation  of  the 
pipe  at  the  face.  In  cases  when  the  draft  does  not  start  readily  and  "la 
estufa  no  quiere"  a  damper  in  the  pipe  at  the  stove  will  overcome  the 
difficulty,  if  kept  closed  until  the  fire  is  going  briskly  and  then  opened. 


18  5lah  of 
Ixj^'lron 


Perforated 
.'Plate 

Hoops 


FIG.  440. CHARCOAL  POT  FOR  VENTILATING  SHAFT. 


This  arrangement  was  not  scientifically  built  or  investigated,  but  it 
worked  well  and  is  handy  where  natural  ventilation  or  compressed  air  are 
lacking. 

Charcoal  Pot  for  Ventilating  Shaft. — During  the  course  of  the  sinking 
operations  at  the  No.  6  shaft  on  the  property  of  the  St.  Louis  Smelting  & 
Refining  Co.,  in  the  Flat  River  district  of  Missouri,  a  charcoal  fire  was 


DRAINAGE  AND  VENTILATION  533 

used  to  induce  ventilation  and  dissipate  rapidly  the  fumes  from  blasting. 
The  fire  was  built  in  an  iron  basket  such  as  is  illustrated  in  Fig.  440.  This 
basket,  filled  with  burning  coals,  is  lowered  to  the  bottom  of  the  shaft 
immediately  after  blasting.  The  heating  of  one  side  of  the  shaft  causes 
an  upward  draft  and  a  down  draft  on  the  other  side. 


INDEX 


Addy,  George  E.,  62,  72 
Ahmeek  Min.  Co.,  125,  144 
Air,  compressed,  for  cleaning  drills,  22 
dump  control,  392 
for  pumping  barrel,  507 

compressor,  10 

hammer,  11 

lifts,  510,  511,  513 

Alaska-Gastineau  Min.  Co.,  177,  267 
Alaska-Treadwell  primer  house,  44 
Alvarado  Cons.  Mines  Co.,  517 
Ambulance  cage,  376 
American  Zinc,  Lead  and  Smelting  Co. 

400 

Anaconda  mines,  timbering,  223,  226 
Angle-sheave  frames,  297 
Angove  skip  dump,  388 
Arc-light  tower,  33 
Argonaut  mine,  signal  system,  340 
Armstrong,  F.  H.,  328,  469 
Auger,  machine-driven,  61 


B 


Backing  block  for  drills,  14,  15 

steam-shovel,  31 
Bag  for  carrying  dynamite,  44 
Bailing  tanks,  383,  384 

bucket,  409 
Baltic  mine,  137 
Bandage  roller,  496 
Barbour,  P.  E.,  4 
Barrow,  roller,  43 
Beard,  H.,  516 

Beaver  Cons.  Mines,  powder  thawer,  49 
Belt  tightener,  10 
Belts,  conveyor,  for  filling,  247 
Bending  tool  for  U-bolts,  21 

rails,  450,  451 

Bennett  mine,  89,  95,  322,  473 
Bergh,  Sven  V.,  62,  76 
Bernard,  Clinton  P.,  88,  348 
Bingham,  Utah,  timbering,  229 


Bins,  ore,  256-262 
Bishop  Creek  Milling  Co.,  409 
Blacksmith-shop,  appliances,  12-13 
Blasting  box  for  sinking,  39 

bulletin  board,  55 

costs,  38 

electric,  40 

Mother  Lode,  35 

fumes,  57 

fuses,  37,  41,  42 

irons,  85 

Mesabi  openpits,  58 

missed-hole  report,  56 

safety  precautions,  53-57 
Bolts,  bending  tool  for,  21 
Botsford,  H.  L.,  291,  322,  415,  419,  509 
Bottomly,  H.,  529 
Bristol  mine,  471,  481 
British  Columbia  Copper  Co.,  35,  204 
Bromly,  A.  H.,  458 
Bucket,  bailing,  409 

connection,  403 

crosshead,  401,  465,  468 

device  to  stop  whirling,  370 

for  drill  steel;  401 

hoist,  324 

hooks,  468 
Buckets,  dumping,  404-409 

on  cableway,  367 

ore,  Joplin,  398 

prospecting,  293,  354 

sinking,  82,  86,  410,  411 
Buildings,  1,  4,  6 

camp,  1 

Bulkhead  doors  514,  516 
Bulkheads,  concrete,  235,  517,  521 

hydraulic  filling,  245 
Bunkhouses,  ventilating,  6 
Bunsen  Coal  Co.,  114,  154,  175 
Burgett,  P.  V.,  291 
Burr,  Floyd  L.,  297 
Burra  Burra  mine,  44,  279,  388,  392 
Buskett,  E.  W.,  401 

Butcher,  E.  W.  R.,  27,  279,  425,  444,  496, 
500 


535 


536 


INDEX 


Butte  &  Superior  mine,  226 
Butte,  Mont.,  timbering,  223 


Cableway  bucket  hoist,  324 

for  trestle  bents,  316 

single-track,  367,  368 
Cactus  mine,  276,  428 
Cage,  ambulance,  376 

and  skip  combined,  379 
transfer,  392 

car  latch,  377 

chairs,  386,  387 

drop-bottom,  371 

gates,  469 

Hancock  No.  2,  82 

safety  catches,  371 

shaft-repair,  376 

testing,  378 
Calkins,  F.  E.,  103 
Calumet  &  Arizona  Min.  Co.,  Junction 

shaft,  90,  107 

Calumet  &  Hecla  mines,  87,  395,  423 
Camp  Bird  mine,  384 
Camp  buildings,  portable,  1 
Cananea  Cons.  Copper  Co.,  266 
Candle  sconces,  250 
Capital  mine,  Colo.,  170,  171 
Capote  mine,  266 
Car-bottom  straightener,  443 

Calumet  &  Hecla,  423 

catch  at  incline  top,  465 

check,  440 

Copper  Range,  415 

Desloge,  418 

Doe  Run,  413 

door  lock,  440 

dumps,  426-433 

for  drill  steel,  436 

latch,  377,  442 

Pickands-Mather,  419 

round-bottom,  413 

safety  hand  grip,  481 

tram,  425 

transfer,  433 

system  in  rockhouse,  433 

wheels,  439 
Cars,  413 

skip,  381,  436 

stockpile,  421,  425 

sublevel,  419,  431 


Carbide  container  and  measurer,  27 
Carter,  E.  E.,  325,  499 
Gary  mine,  Wis.,  135,  186 
Cascade  Min.  Co.,  174 
Catlin,  R.  M.,  280,  344 
Cavagnaro,  D.  A.,  406 
Cement  gun,  135 
Century  mine,  Mo.,  236 
Chairs,  cage,  386,  387 
Champion  Mine,  Mich.,  15,  138 

concrete  station,  162 
Change  house,  Copper  Queen,  483 
Homestake,  488 
Republic  Iron  &  Steel  Co.,  485 
United  Verde,  487 
Channel  Mining  Co.,  406 
Chapin  mine,  127 
Chapman,  Temple,  235 
Charcoal  pot  for  ventilating,  532 
Chief  Cons.  Min.  Co.,  376 
Christensen,  A.  O.,  507,  511 
Chute  and  gate,  Creighton  mine,  262 

bulldozing,  267 

conveyor,  255 

door,  safety,  474 

gates,  263,  267,  274-279 

sliding  for  sinking,  411 

spray,  501 

steel-protected,  273 
Chutes,  262-273 

concrete  storage,  271 

for  loading,  270,  273 

hanging,  271 

steel,  252 

Cinderella  Cons.,  sand  filling,  237 
Cleveland-Cliffs  Iron  Co.,  66,  234,  251, 

378,  478,  504 
Clip  for  wire  rope,  366 
Colby  Iron  Min.  Co.,  315 
Collars,  shaft,  138,  141,  470 
Collins,  G.  E.,  171 
Collins,  S.  J.,  20 
Compressed  Air,  see  "Air.  " 
Compressor,  air,  10 
Concklin,  B.  M.,  43 
Concrete  bulkheads,  235,  517,  521 

drop  shaft,  142 

headframe,  287 

hoisting  pocket,  155 

in  shaft,  90,  103-143 
costs,  113 

latrine,  493 


INDEX 


537 


Concrete  plant,  Oliver  Iron  Min.  Co.,  131 
sets  molded  on  surface,  125 
shaft  collars,  138,  141 

station,  156-162 
storage  chutes,  271 
stringers,  144-147 
Conveyor  belts,  see  "  Belts." 
Conveyors,  underground  trolley,  333 
Copper,  mass,  cutting,  60 
Copper  Queen  Co.,  155,  250,  271 

change  house,  483 
Copper  Range  Co.,  drill  column,  69 
ladders,  174 
skip  dump,  388 
car,  415 

Corundum  mine,  523 
Costs,  concrete  bulkheads,  521 
Golden  Cross  mine,  214 
Mother  Lode  mine,  208 
shaft,  concreting,  113 

sinking,  38 

timber  headframe,  287 
tunneling,  182 
Creighton  mine,  150,  262 
Cripple  Creek,  ventilation,  522 
Crossheads,  bucket,  401,  465,  468 
Crossings,  track,  453 
Crossover,  track,  460 
Crushing,  underground,  150 


Davenport,  L.  D.,  80,  96,  131,  148,  217, 

222,  271,  283,  352,  355,  376,  410, 

411,  431 

DeCamp,  W.  V.,  37 
Delay-action  fuses,  37 
Del  Mar,  Algernon,  409 
Denny,  G.  A.,  93,  285 
Derrick  for  loading  at  collar,  369 

sinking,  287,  322 
Desloge  Cons.  Lead  Co.,  22,  188,  386, 

429,  470 
car,  418 

Dickson,  Robt.  H.,  90,  107 
Dober  mine,  Mich.,  186 
Doe  Run  Lead  Co.,  371,  413,  427 
Drag  scraper  for  dump,  366 
Drainage  and  Ventilation,  504.     See  also 

"Pumps"  and  "Unwatering." 
Draining  in  chutes,  165 

water  bulkhead,  514,  516 


Drift,  removing  ore  from,  220 
rounds,  182-192 

Leyner,  182 
timbering,  192,  220 
Drifting,  177 

St.  Joseph  Lead  Co.,  190 
with  a  stoper,  192 
Drill-arm  steadier,  67 
bolts,  22 

clamp,  repairing,  72 
column  arm,  67 
collar,  68 
Copper  Range,  69 
pneumatic,  62 
machine,  supports,  62 
parts,  cleaning,  22 
removing  broken,  62 
steel,  failure  and  heat  treatment,  76 
handling,  and  tramming,  63,  70, 

401,  436 
heating  and  tempering,  14,  15,  19, 

21 

sharpening,  13,  17,  20,  71 
tester,  North  Star,  73 
tripod  set-up,  66 
Drilling  kinks,  58 

Mesabi  gopher  holes,  58 
rounds,  164,  182-192 
with  augers,  61 
Drinking-water  cooler,  32 

fountain,  499 

Drywalls,  Sudbury  district,  197 
Dump  cars,  see  "Cars." 
drag  scraper  for,  366 
for  sublevel  car,  431 
hook,  468 
skip,  388,  389 
control,  392 
Dumps,  bucket,  404-411 

car,  426-433 
Dumping  trestle,  313 
Durfee,  E.  W.,  32 
Dust-laying  device,  for  chutes,  501 
Dwellings,  miners,  4,  6 
Dynamite,  see  " Explosives,"  "Powder," 
etc. 


E 


Eades,  Chas.  B.,  103 
East  Vulcan  mine,  angle-sheave  frame, 
302,  304 


538 


INDEX 


Edyvean,  E.  H.,  471 
Ellamar  Min.  Co.,  259 
Empire  Copper  Co.,  24 
Engines,  foundations,  8 
Explosives,     35.     See     also     "Powder," 
"Blasting." 


Federal  Lead  Co.,  cage  and  skip,  379 

cars,  420,  439 

dump,  427 
Feed-water  heater,  6 
Fields,  Dan,  21 

Filling,  distributing  by  conveyor  belts, 
247 

hydraulic,  245 

sand,  bore-hole  system,  240 

Cinderella  Cons.,  237 
Finney,  W.  J.,  353 
Fire-fighting  system,  498 
First  aid,  bandage  roller,  496 

resuscitation,  497 

stretcher,  498 

Five-hole-cut  raising  method,  164 
Flannigan,  W.  H.,  382 
Fleeting  device  for  hoist,  287,  328 
Flooding  of  mine,  521 
Foote,  F.  W.,  226,  366 
Forbes,  C.  R.,  305,  307 
Forge,  blacksmith,  12,  13 
Foster,  Allen  H.,  479 
Foundations,  engine,  8 
Franklin  Min.  Co.,  329 
Fuller,  John  T.,  192,  440 
Fumes,  blasting,  57 
Furnace  for  heating  drill  steel,  14,  15 
Fuse-cutting,  41,  42 
Fuses,  delay-action,  37 


G 


Gage-iron  for  track,  450 
Gagnon  mine,  225 
Gate  latch,  473 

skip-pocket,  283 
Gates,  cage,  469 

chute,  263,  267,  274-278 
safety  lever,  279 

shaft,  472,  473 
Gieser,  H.  S.,  529 
Ginpole,  built-up,  317 


Ginpole  for  handling  stack,  319 

of  10-in  pipe,  318 
Giroux  Cons.  Mines  Co.,  11,  392 
Goldsworthy,  Jos.,  365,  403 
Go-devil  incline  plane,  329 

car,  332 

Gold  Hill  &  Iowa  Mines  Co.,  325,  499 
Golden  Cross  mine,  stoping,  209 

costs,  214 

Gong  for  underground  motor,  476 
Goodwin,  L.  Hall,  70,  273,  327,  397 
Gopher  holes,  Mesabi  range,  58 
Grade  board  for  steam-shovel  work,  29 

stick  for  tracks,  449 
Gravity  planes,  329 
Griggs,  C.  C.,  10 

Guanajuato  Red.  &  Mines  Co.,  98 
Gunite  on  shaft  lining,  135 
Gustafson,  Oscar,  315 
Guy  lines,  elevating,  33 


II 


Haight,  Clarence  M.,  28,  280,  361,  369 
Hall,  Albert  E.,  150,  154,  197,  262,  393, 

491 

Hambley,  William  B.,  393,  491 
Hamilton  shaft,  relining,  127 
Hammer,  air,  for  blacksmith  forge,  11 
Hancock  No.  2  shaft,  67,  82,  85 

station,  160,  282 
Harold  mine,  233,  251,  449,  463 
Hart,  W.  C.,  389 
Hartman,  W.  F.,  144,  158 
Haulage,  inclined,  361 

safety  device,  476-482 
Headframe,  A-type,  285 
costs,  287 

concrete,  287 

for  timber  shaft,  354 

prospecting,  291,  292 

small  four-post,  291 

temporary,  291 

tripod,  292 

with  guy-rope  bracing,  284 
Heap,  R.  R,,  514 
Heater  for  feed  water,  6 
Henrotin  chute,  263 
Hewitt,  A.  J.,  49 
Hibbert,  E.,  35,  204 
Hibernia  mine,  517 
High  Ore  mine,  223 


INDEX 


539 


Highland  Boy  mine,  251 

Kingston,  E.  C.,  30 

Hirschberg,  C.  A.,  182 

Hobart,  E.  M.,  401 

Hocking,  Jos.,  364 

Hodge,  W.  R.,  10,  44,  278,  296,  343,  388, 

392 
Hodgkinson,  H.  H.,  164,  220,  226,  269, 

344,  361,  474,  481 
Hoist,  bucket,  324 

chain-driven  convertible,  325 

fleeting  device,  287,  328 

foundations,  8 

Otis  Elevator,  325 
Hoisting  in  balance,  327 
Hoisting,  Lowering,  Transporting,  324 

over  a  summit,  334 

pocket,  155 

prospect  shaft,  296 

record,  329 

ropes,  357,  361-366,  463 

safety,  463-469 

sheaves,  287,  288,  297 

signaling,  349,  463,  464 
Homestake  change  house,  488 
Hook,  cage  testing,  378 

dump  for  bucket,  468 

for  hauling  timbers,  235 

safety,  332,  468 

to  support  staging,  232 
Hooks,  safety  bucket,  468 
Houghton  mine,  327 
Hydraulic  filling,  245 


Idlers,  rope,  357 
Incline,  safety  devices,  465 
Indiana  Min.  Co.,  142 
Interstate  Iron  Co.,  166 
Iron-ores,  soft,  timbering,  222 
Isabella  mine,  Mich.,  174 
Ives,  L.  E.,  33,  325 


J 


Jackson,  G.  J.,  267 
Jessup,  D.  W.,  229,  453 
Jobe,  W.  H.,  472,  473,  481 
Johannes  shaft,  373 
Johnson,  J.  M.,  and  O.  R.,  329 
Jones,  E.  R.,  125 


Jones,  S.  S.,  382 
Jones,  Wm.  W.,  53,  465 
Joplin  district,  235 

buckets,  398,  404,  468 

cars,  436 

drill  sharpening,  17 

whim,  356 

Junction  shaft,  concreting,  90,  107 
Jupiter  mine,  529 


K 


Keating  chute,  264,  265,  266 

Kellogg,  L.  O.,  169,  199,  287,  322,  350, 

381,  461 

Kennedy,  E.  P.,  44 
Kennedy  mine,  377,  420,  442 
Kidston,  W.  L.,  261 
Kimball,  Clinton,  308 
Kimberley  diamond  mines,  440 
Kingdon  shaft,  concrete  lining,  103 
Kneip,  Leo.  H.  P.,  173 
Krause,  Herbert,  334 


Ladders,  167-176,  233 

Lake  mine,  turn  sheaves,  307 

Lamps,  acetylene,  27 

Laramie-Poudre  tunnel,  187,  188 

Latrines,  491,  493 

Lawson  chute,  263 

Lee,  Howard  S.,  505 

Leland,  Frank  M.,  24 

LeVeque,  G.  E.,  292 

Leyner  drilling  rounds,  182 

Lighting,  surface,  33 

Lincoln  mine,  Minn.,  166 

Linke,  H.  A.,  92,  169,  349,  408 

Little  Mary  mine,  521 

Little  Nell  mine,  527 

Loading  arrangements  underground,  150, 

270 
Quincy  mine,  273 

derrick,  369 

pockets,  N.  J.  Zinc  Co.,  280 

station,  tracks,  444 
Locomotive,  underground,  476 
Longacre- Chapman  mine,  236 
Lowering  devices,  329 

drill  steel,  401 

in  balance,  354 

timber-truck,  438 


540 


INDEX 


Lowering  windlass,  355 
Lubricating  hoisting  rope,  365 
Lucania  tunnel,  Colo.,  185 
Lunt,  Horace  F.,  8 


M 


McConnell  Mines  Co.,  20 

McFarland,  J.  R.,  10,  11,  276,  392,  405, 

428 

McGill,  M.  J.,  513 
Macdougall,  C.  W.,  91 
Machine  bar,  64 

drill  supports,  62 
Magazine,  powder,  46,  49 
Magnus,  B.,  498 
Manway-and-skipway  door,  95 

protective  combing,  474 
Marcellus,  Roy,  465 
Marshall,  Emory  M.,  20 
Mason  Valley  Mines  Co.,  21,  460,  501 
Mascotte  tunnel,  Utah,  478 
Matthews,  J.  P.,  508 
Mawdsley,  W.  H.,  57 
May,  Karl  A.,  307 
Mentzel,  Chas.,  292 
Merrill,  Pomeroy  C.,  219 
Mesabi  range,   131,  148,  279,  283,  352, 
376,  425,  431,  444,  496 

drilling,  58 

timbering,  96,  195,  222,  355 

top-set  slicing,  217,  219,  232,  271, 

449 

Midget  mine,  523,  526 
Mine  water,  bulkhead  door  for,  514,  516. 

See  also  "Drainage,"  etc. 
Minnesota    iron    mines,  see    "Mesabi" 

and  names  of  mines. 
Mohawk  mine,  87 

shaft  collar,  138 
Monarch-Pittsburgh  shaft,  56 
Mond  Nickel  Co.,  491 
Montgomery  mines,  N.  C.,  5 
Moore,  L.  C.,  504 
Moore,  S.  R.,  42 
Moose  Mountain  mine,  334 
Mother  Lode  mine,  B.  C.,  35,  204 

costs,  208 

Mount  Morgan  mine,  498 
Muir,  Douglas,  98 
Mules,  shoeing,  482 
Munzner  safety  catches,  371 


N 


Naumkeag  Copper  Co.,  325 

Negaunee  No.  3  shaft,  116 

New  Jersey  Zinc  Co.,  164,  280,  344,  361, 

369,  498 

New  Kleinfontein  mine,  334 
Newberry,  A.  W.,  209 
Newport  Mining  Co.,    Palms  shaft,  39, 

121 

Norrie  mines,  320 
North  mine,  N.  S.  W.,  247 
North  Star  drill  tester,  73 

gravity  planes,  329 

stoping,  199 

O 

Gates,  Herbert,  41 

Oke,  A.  Livingstone,  8,  13,  316,  317,  319, 

366,  450 

Old  Dominion  Co.,  103 
Oliver  Iron  Mining  Co.,  31,  97,  277,  318 
350,  356,  474,  476.     See   also 
names  of  individual  mines, 
concrete  plant,  131 
Ore  buckets,  chutes,  etc.,  see  under  name 

of  article. 

removing  from  drift,  220 
Orser,  Edw.  H.,  449 
Otis  Elevator  hoist,  325 


Pacific  Copper  Mining  Co.,  37- 

Packard,  George  A.,  335 

Palms  shaft,  39,  121 

Paynter,  W.  D.,  drill  tester,  73 

Pedersen,  A.  B.,  376 

Penn  Iron  Min.  Co.,  169,  298,  328,  342 

Perseverance  mine,  177,  267 

Pickands,  Mather  &  Co.,  135 

car,  419 

Pickard,  H.  G.,  491 
Pillar  extraction,  235 
Pipe  joint,  11 

-line  anchor,  10 
steam,  321 

lines,  fire,  498 

rack,  25 

rollers,  360 
Pipes,  ventilating,  529 


INDEX 


541 


Plates,  iron  bending,  22 
Pocket  and  station  in  ore,  148 

for  spillage  and  sinking,  154 

hoisting,  155 

skip,  155,  280,  282 

storage,  271 
Portland  mill,  366 
Powder,  bag  for  carrying,  44 

chutes,  43 

house,  see  "  Magazine." 

magazines,  46,  49 

storage  and  thawing,  44-52 
Power  plant,  6 
Praetorius,  E.,  367,  368 
Primer  house,  44 
Primers,  46,  53 
Pringle,  L.  B.,  29,  31,  266 
Prospecting  bucket,  354 

headframes,  291,  292 

hoisting  arrangements,  296,  352 

machinery  foundations,  8 
Pump  and  air  lift  combined,  510 

arrangement,  economical,  505 

compressed  air,  507 

hand,  homemade,  506 

station,  suction,  509 

valve,  508 

Pumps,  see  also  " Drainage"  and  "Un- 
watering." 

turbine,  504 
Pumping  barrel,  507 

Q 

Quincy  mine, 

drill  handling,  70 
drilling  round,  186 
loading  chutes,  273 
skip  ropes,  397 

R 

Rail  and  tie  holder,  452 
Rails,  bending,  450,  451 
Raimund  mines,  485 
Rainbow  mine,  505 
Rainsford,  R.  S.,  340 
Raise,  draining,  165 

scaffolding,  164 

tops,  protecting,  474 
Raising,  164 

five-hole-cut  method,  165 


Rasmussen,  C.  M.,  364 

Raven  mine,  Butte,  335,  357 

Rayas  mine,  98 

Recording  mine  timbering,  192 

Red  Jacket  car,  423 

Reifsneider,  Le  B.,  63 

Reno,  J.  E.,  521 

Republic  Iron  &  Steel  Co.,  27,  279,  425, 

444,  485,  496,  500 
change  house,  485 
Republic  Iron  Co.,  316,  324 
Resuscitation,  497 
Reversing  hoisting  rope,  363,  364 
Rice,  Claude  T.,  15,  17,  22,  46,  82,   142, 
144,    156,    160,   282,   415,   427, 
477,  479 

River  breaks,  521 

Robinson  Deep  mine,  sand-filling,  240 
Rock  Drills,  see  " Drills." 
Rockhouse,  car-transfer  system,  433 
Rogers-Brown  Ore  Co.,  464,  508 
Roller  barrow,  437 
Rollers  and  sheaves,  357-363 

substitute  for,  361 
Rollin,  Geo.  S.,  1,  6 
Roosevelt  tunnel,  186,  187 
Rope  guide  to  sheaves,  361 

idlers,  357 

hoisting,  357,  361-365,  463 

lubricating,  365 

reversing  on  drum,  363,  364 

skip,  holding,  397 

wire,  bending,  365 
clip,  366 
socketing,  365 

Rork,  Frank  C.,  164,  334,  468 
Rosas  mine,  Sardinia,  367 
Rosewall,  Jas.,  233 
Rosiclare  Lead  &  Fluorspar  Co.,  339 
Rowland,  L.  G.,  344 
Royce,  Stephen,  135 
Rule,  R.  A.,  67,  68 


S 


Sacramento  shaft,  155 
Safety  and  sanitation,  463 

block  for  incline  top,  465 
catches,  cage,  371,  378 
crosshead,  465,  468 
door  for  chutes,  474 
hand  grip  for  car,  481 


542 


INDEX 


Safety  haulage  devices,  476-482 
hooks,  332,  468 
in  blasting,  53-57 

hoisting,  463-469 
lever  for  chute  gates,  279 
shaft  guards,  470-473 
St.  Joseph  Lead  Co.,  190,  427 
Saint  Louis  Smelting  &  Refining  Co.,  33, 
46,  55,  88,  275,  284,  287,  371, 
387,  413,  426,  433,  444,  482,  532 
Sand  filling,  see  "Filling." 
Sanders,  Wilbur  E.,  256 
Sanitary  fountain,  499 
Sawyer,  A.  H.,  485 
Scaffolding  in  untimbered  raise,  164 
'Scallon,  E.  P.,  165 
Schley  mine,  500 
Schultz,  R.  S.,  Jr.,  363,  364 
Sconces,  candle,  250 
Scott,  Herbert  K,  368 
Scraper,  drag,  366 
Semple,  C.  Carleton,  40 
Septic  tanks,  494 

underground,  491 
Shaft  bar,  472 

collars,  138,  141 

guards,  470,  471 
concrete,  142 
Shaft  Conveyances,  371 
Shaft-door,  hinge,  88 
gates,  472,  473 
lining,  concrete,  103-137 
Junction  shaft,  90,  107 
Kingdon  shaft,  103 
Palms  shaft,  121 
steel,  121 
with  gunite,  135 
platform,  hanging  bracket,  89 
raising  and  enlarging,  116 
repair  cage,  376 
sets,  blasting  irons  for,  85 
sinking,  37,  86,  287,  352 
cage  and  bucket,  82 
costs,  38 

Hancock  No.  2,  67,  82,  85 
Palms  shaft,  39,  121 
without  timber,  88 
stations,  148,  156,  160,  162 
timber,  96,  354,  355 
timbering,  80,  91,  92,  93,  97 
untimbered,  88,  98 
unwatering,  98,  504,  505,  511,  513 


Shaft  ventilation,  532 
Shafts  and  Raises,  80 
Shaw,  E.  S.,  262 
Sheave-wheel  lining,  363 
Sheaves,  361 

turn,  297,  305,  307 
Sheep  Creek  tunnel,  177 
Shelby,  W.  W.,  270,  422 
Sheldon,  G.  L.,  363 
Shop  appliances,  1 1 
Shower  bath,  homemade,  500 
Signal  bell  for  topman,  349 

box,  electric,  343,  345 

hoisting,  349,  463,  464 

system,  Argonaut  mine,  340 
bare-wire,  342 
electric,  335 

for  electric  tramming,  350 
locked,  344 

wire  arrangement  in  sinking,  348 
Silver  King  Consolidated  mine,  513 
Simmer  &  Jack  mine,  sand-filling,  240 
Sinking,  see  also  "Shaft  Sinking." 

buckets,  82,  86,  410,  411 

with  derrick,  287 

windlass,  352 

Skip  and  cage  combined,  379 
transfer,  392 

-bail  lock  and  release,  382 

cars,  381,  436 

-changing  carriage,  393 

dog,  388 

dump,  Angove,  388 
control,  392 
plate,  389 

inclined,  381 

Skip  pockets,  155,  280,  282 
gate,  283 

recorder,  329 

rope,  holding,  397 

safety  device,  465 

stringers,  144,  145,  147 

transfer,  395 
Skipway  door,  95 
Smith,  B.  H.,  56" 
Smith,  Fred.  D.,  11 
Smither,  Thos.  M.,  354 
Smuggler-Union  mine,  422 
Socavon  de  la  Virgen  mine,  384 
Sohnlein,  M.  G.,  384 
Sommers,  John,  21  :m 

South  Blocks  mine,  252 


INDEX 


543 


South  Utah  Mines  &  Smelters,  276,  428 
Spanish- American  Iron  Co.,  63 
Spaulding,  Chas.  F.,  451 
Spillage  and  sinking  pocket,  154 
Stack,  setting  with  ginpole,  319 
Stages  built  with  ladders,  233 
Staging,  hook  and  staple,  232 
Stairway  for  vertical  shaft,  175 
Stations,  shaft,  148,  156,  160,  162 
Steam-line  supports,  320 
-shovel  teeth,  28 

grade  board,  29 

track  connection,  30 

backing  block,  31 
Steel,  drill,  failure  and  heat  treatment,  76 

handling,  63,  70,  401,  436 

heating  and  tempering,  14,  15,  19, 
21 

sharpening,  13,  17,  20,  71 
Sterling  Iron  &  Ry.  Co.,  12,  287,  381,  446 
Steward  mine,  Butte,  225 
Stockpile  trestle,  315,  318 

car  for,  421,  425 
Stope  pocket,  concrete,  271 
Stoper,  drifting  with,  192 
Sloping,  199 

Golden  Cross  mine,  209 
Mineville,  N.  Y.,  215 
Mother  Lode  mine,  204 
North  Star  mine,  199 
shrinkage  system,  226 
Stove  ventilator,  531 
Stratton's  Independence,  Ltd.,  262 
Stretcher,  underground,  498 
Stringers,  skip,  144,  145,  147 

repair,  448 

Sublevel  cars,  419,  431 
Success  mine,  Idaho,  42 
Suction  for  pump,  509 
Surface  Plant  and  Operation,  1 
Swift,  T.,  531 
Switch  for  signaling,  351 
Switches,  458 

and  crossings,  453 
Syndicate  mines,  Butte,  223 


Tank  cars,  434 

for  treating  timber,  322 
wooden  substructure,  320 

Tanks,  septic,  491,  494 

Tempering  drill  steel,  15,  19,  21 


Tennessee  Copper  Co.,  279,  388,  392 

Test-pit  windlass,  352 

Testing  drills,  North  Star  mine,  73 

cages,  378 

Thawing,  see  " Powder." 
Thoenen,  J.  R.,  273 
Threeman  mine,  Alaska,  261 
Timber  bins,  256,  259,  261,  262 

dams  for  filling,  246 

framer,  24 

headframe,  see  "Headframes." 

preservation,  322 

shaft,  96,  354,  355 
Timber  Structures,  256 

truck,  438 
Timbering  at  switches,  226 

Butte,  223 

drift,  192,  220 

in  shrinkage  stoping,  226 

Mesabi  range,  96,  195,  222,  355 

mine,  recording,  192 

shaft,  80,  91-93,  97 

station  and  pocket,  149 

top-slice,  Bingham,  229 

underground  turns,  195 
Timbers,  hook  for  handling,  235 

square-set,  222,  223 
Tippett,  F.  H.,  174 
Tipples,  see  "Dumps." 
Tom  Reed  mine,  382 
Top-set  slicing,  217,  219,  232,  271,  449 

-slice  timbering,  Bingham,  229 
Track,  444 

arrangement,  inclined  shaft,  446 

crossover,  460 

curves  in  top-slice  rooms,  449 

laying,  449 

steam-shovel,  30 

switches,  453,  458 

turnout  for  narrow  drift,  460 

turntable,  461 

turns,  timbering,  193 
Tracks  for  loading  station,  444 
Tramming  trestle,  314 

underground,  signaling,  350 
Transfer  car,  433 

for  cage  and  skip,  392 

skip,  395 

system  in  rockhouse,  433 
Trestle-bent  dimensions,  tabulating,  308 

bents,  erecting,  316 

dumping,  313 


544 


INDEX 


Trestle  for  motor  tramming,  314 

raising  without  ginpole,  316 

stockpile,  315,  318,  421,  425 
Trestles,  308 

coal,  310 

Tripod  set-up  for  drills,  66 
Trolley  conveyors  underground,  333 

wires,  protecting,  477,  479,  480,  481 
Trolleys  for  sinking,  87 
Truck  for  lowering  timber,  438 
Tunnel,  Laramie-Poudre,  188 

Lucania,  185 

Sheep  Creek,  177 
costs,  182 

Roosevelt,  187 

ventilation,  531 
Turnout  for  narrow  drift,  460 
Turn-sheave  types,  297 

location  and  support,  305 
Turn  sheaves,  Lake  mine,  307 
Turntable,  461 


U 


U-bolt  bending  tool,  21 
Uncle  Sam  Mining  Co.,  10 
Underground  crushing  and  loading  ar- 
rangements, 50 
U.  S.  Bureau  of  Mines,  497 
United  Verde,  change  house,  487 

latrine,  493 

septic  tanks,  494 

Un watering  Little  Mary  mine,  521 
shafts,  98,  504,  505,  511,  513 


Ventilation  control,  door  for,  529 

pipes,  529 

pressure,  Cripple  Creek,  522 

shaft,  532 

tunnel,  531 
Verona  Min.  Co.,  473 
Vivian,  Arthur  C.,  395 


W 


Wakefield  mine,  Mich.,  389 
Wallace,  R.-B.,  147,  316,  324,  365 
Wass,  H.  R.,  339 
Water,  bulkhead  door,  514,  516 

channels  into  mine,  plugging,  521 

drinking,  32,  499 

West  Vulcan  mine,  turn  sheaves,  298 
Weston,  E.  M.,  333 
Wheelbarrow,  437 
Wheels,  car,  439 
Whim,  Joplin  type,  356 
Whiting,  Lowe,  468 
Wiard,  E.  S.,  170,  171 
Windlass,  352,  355 
Winze,  bailer  for,  383 
Wire  rope,  see  "Rope." 
Wires,  trolley,  protecting,  477,  479,  480, 

481 

Witherbee,  Sherman  &  Co.,  52 
Wolcott,  G.  E.,  192 
Wolf,  Albert  G.,  21,  272,  352,  460 
Wolverine  shaft,  141,  156 
Worcester,  S.  A.,  383,  522 


Valve,  pump,  508 
Ventilation,  bunkhouses,  6 
charcoal  pot  for,  532 


Yates,  B.  C.,  488 


Zenith  mine,  472 


THIS  BOOK  IS  DUE  ON  THE  LAST  DATE 
STAMPED  BELOW 


AN   'INITIAL     FINE     OF     25     CENTS 

WILL  BE  ASSESSED  FOR  FAILURE  TO  RETURN 
THIS  BOOK  ON  THE  DATE  DUE.  THE  PENALTY 
WILL  INCREASE  TO  SO  CENTS  ON  THE  FOURTH 
DAY  AND  TO  $1.OO  ON  THE  SEVENTH  DAY 
OVERDUE. 


FEB    131933 


stf 


REG.  CIR.  m    5  "83 

MAY  1  R  1999 


JAN  29  1936 

JAN    9    1 
OCT  17 

APR  27 1983 


LD  21-50m-l,'3£ 


A   _ 


.X 


YC 


331169 


UNIVERSITY  OF  CALIFORNIA  LIBRARY 


